Communication
“All poetry has to do is to make a strong communication.” ~ English poet Stevie Smith
Communication is transmitting information. Neither reception nor behavior is necessary for communication to occur. A futile cry for help – to no reception – is still a communication.
Reception often differs from the intended signal; a dissonance known as miscommunication.
To signal is to intentionally send a communiqué. Signaling is necessarily reactive, in having an originating stimulus, though that stimulus may be nothing more than the passing of time.
As communication is often unintentional, volition does not belong in its definition. Communication may lie outside behavior, and, by logical extension, outside life itself. Nature is constantly communicating.
More mundanely, we tend to think of communication as being between beings. But communication is also within an organism: between cells, and even between molecules within cells. In all instances, the essence of communication is ecological information.
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Sensation is internal communication of sensed external stimuli and information about the quality of its reception: sensation includes the status of the sensory apparatus, as well as its substantive uptake. (Information about sensory quality typically goes unnoticed. It is only when our senses seem amiss, such as during sickness, do we become aware of that aspect of sensation.)
During perception, the mind symbolically synthesizes sensation, determining its meaning. Perception references knowledge, which may either be from experience or innate. Sensation and perception are both internal communications.
Behavior is driven by concepts which are deemed meaningful. Meaningless perceptions are ignored.
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To be in the world is to communicate. Such is the entanglement of life.
“All behavior is communication.” ~ American communication scholar Paul Watzlawick et al
Signaling sometimes involves a level of indirection. The fruit that advertises its ripeness is communicating on behalf of the seeds inside. Fruit past its prime is a different communiqué.
Floweradvertisements and potential prey warnings are exemplary communications. Blossoms have nectar guides which communicate a beeline to a treat.
Patterns of high contrast on a flower are particularly attractive to bees. As all vision systems are keyed to contrast, flower patterning is an attribute of visual communication attuned to an intended receiver.
Flowers with conical petal cells, such as roses, provide adhesive grips that let a bee grab onto when it is windy. This is an example of communicated convenience as a morphological trait.
Indigestible animals sport loud spots, outrageous coloration, or other identification to ward off predation. Some free riders mimic the inedible species, to gain the same protection without packing the poison.
Mimicry is specific signaling. Though an unappreciated communiqué to all but its sender, camouflage is often not even a behavior.
Fake Feces
Though there are exceptions, most animals avoid dung as an unsanitary hazard. A well-known exception are flies, which feast on fresh feces. Therein opportunity lays like a platter if only one can resemble a fecal splatter.
The orb-weaving spidercovers its web with blotchy white decorations that resemble bird droppings. Its silver body blends in. The effect fools wasps upon which spiders dine.
Long before Asian swallowtailsemerge into beautiful black-and-white butterflies, their caterpillars look like little logs of bird poop. This disguise dissuades potential predators when the young logs are most vulnerable.
The bird-dung crab spider in Singapore both looks and smells like shit. This crappy deception attracts tasty flies. Looks do kill, but it’s the scent that keeps them coming.
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Although protective coloration provokes no direct behavioral response, being overlooked by a predator is a non-response that qualifies as behavior, as inaction is as much behavior as action.
“The surfaces of bodies of water aren’t the commonest of habitats, but a decent number of creatures are specialized for getting around on it.” ~ American zoologist Steven Vogel
A water striderrests on the surface of a pond, its feet (tarsi) repelling water while allowing the insect to support itself by water tension. Tarsi-invoked ripples let one water strider communicate with another. A water strider can tell the sex of another by its ripple messages.
Those same tarsi pick up ripples as a fly struggles on the water’s surface; signals of a meal-to-be. To a water strider, this is a warbling monologue in good taste.
Raft spiders that live in bogs independently evolved the water strider technique of using a water surface as a virtual web.
Telltale Smell
Mosquitoesfind succulent humans and other beasts by sniffing them out. Even a minute emission of nonanal (C9H18O) – an oil which humans exude from their skin – invites a mosquito.
The mosquito’s daily biorhythm gears up its olfaction equipment so that mosquitoes’ sense of smell is better at night than during the day, when it is asleep. As victims can’t see it coming, nighttime is the right time for bloodsucking.
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The prey that gives itself away implies that sheer corporeality is communication. So it is.
Exchanging chemical compounds is common to all life. However hard-pressed one might be to call viral invasion aggressive negotiation, it often is just that.
Many viruses can mimic a host cell protein or other cell component responsible for initiating a defense response, and so can get on with their business of infection without interference. In this instance, stifling normal signaling qualifies as communication, albeit a sly one indeed.
Metacommunication
Metacommunication is a communicationqualifier: a way of contextually qualifying behaviors that follow.
Cleaner Fish
Cleaner fishsport a uniform that identifies them by occupation. They have a contrast-enhancing black lateral body stripe that non-cleaning fish lack. Clients also recognize cleaners by their colors, particularly blue and yellow on certain body parts. These characteristic colors make the highest contrast against a reef background.
Cleaner fish dance before a potential client to signal their intent; a metacommunication that induces the much larger fish to reserve its predatory instinct and wait passively to be cleaned.
Having recognized the uniform and advertisement, a potential client fish that might otherwise consider a cleaner a decent meal instead decides to communicate an all-clear signal for cleaning: another metacommunication of intent. After all, food isn’t hard to find on the reef; but a good cleaning – well, that’s a service.
When a fish has had enough of having its mouth cleaned, it jerks its jaw in a certain way to tell the cleaner that it is time to move on. The otherwise risky marine ectoparasite removal business relies upon interspecies metacommunication.
Play
Carnivores posture as an invitation to play. An adult male lion invites a cub to play by bowing before the cub (forequarters lowered): a gesture that has no other context, and an indicator that any aggressive actions that follow are play. Wolves, coyotes, and dogs use the same posture, and may wag their tails during play fights. Dog tail-wagging with humans is an indication of happiness akin to that when playing.
Young monkeysspend most of their time playing with each other. Howler monkey and gibbon infants chirp at each other to indicate that the actions that ensue are playful in intent. Other monkeys display a play face.
Playful aggression is part of behavioral development in a carnivore: for example, stalking and attack practice. In social animals, learning social graces, especially acceptable limits of aggression, are necessary for a successful life.
Cellular Communication
“Tunable interplay of self-communication and neighbor communication enables cells to span a diverse repertoire of cellular behaviors.” ~ cytologists Hyun Youk& Wendell Lim
Cells are the atoms of life. Both are organized on energetic relations.
Similarly, cellular communication is analogous to the dynamics of inorganic existence; the relations between subatomic particles, and between atoms in molecules. There is continuous interaction in all instances.
“Cell polarity is critical for the specialized function of the vast majority of cells.” ~ American molecular biologist Rong Li
Electrical potentials provide beacons of cellular organization and status. Cells construct polarity to facilitate spatial orientation within, allowing parts of a cell to understand where they are in relation to others.
To engender polarity, enzymes carefully arrange phospholipids, which are a major component of cell membranes. This alters the map of electric charges in a cell, helping shape a coherent terrain for cellular molecules to comprehend. Besides their structural role in assisting intracellular molecular orientation, phospholipids facilitate intercellular signaling.
Subatomic particles form an atom via communication. Bosons urge fermions into coherent relations. Intracellular communication functions similarly.
In organisms, biomolecules, such as proteins, are not just conglomerated atoms. They are a continuing community: in constant communication with each other.
Multicellular bodies also function as a society. Cellular actions and interrelations often follow rules of economy, just as molecular bindings and interactions adhere to their own set of energetic conventions.
Cells communicate within and without. Every cell has its own internal network. Outside is an external network: the cacophony of the neighborhood to which a cell belongs, as well as long-distance missives from conspecific cells.
Conspecific refers to the same type or species. Interspecific is of different species or varieties.
“Membrane signaling is fundamental for almost all aspects of life because that’s how information gets from outside cells to inside cells.” ~ American biochemist Adam Cohen
Elaborate sets of communication channels and protocols exist in all cells: to track events within, to procure supplies and avoid hazards from without, to fight invasion, to grow, divide, repair, to pick up on neighborhood news, and receiving marching orders to serve an organism’s greater good. Cellular communication is part of a gyre of information gathering and retention, frequently leading to decisions that initiate a new round of communication.
A cell never loses its sense of self, but its mandate is to serve its organism rather than just its own needs. Without this, eukaryotes could not develop and function, nor prokaryotes socially aggregate to greater success than individuals could ever achieve.
Cells in a multicellular organism are often not symmetrical. The cells in an animal’s intestines, for instance, need to know which side faces into the intestines, and which faces out, toward the rest of the body. This requires coordination and communication, both with neighboring cells and within, for the cell to allocate resources and process operations in the right place at the right time. Different genes are expressed in different parts of a cell to accomplish this.
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Cell signaling comprises the complex set of communication protocols that cells employ for messaging, whether within or without. In its vast diversity, cell signaling is easily one of the most intricate realms in biology.
Signal transduction defines the 2-step process of intracellular communication. 1st, an extracellular signaling molecule activates a receptor on a cell surface.
Surface reception prompts creation of another molecule, termed a 2nd messenger, which carries the signal to a target molecule within the cell; often, either in the nucleus or cytoplasm. Reception of the 2nd messenger within a cell organelle typically eventuates in a response.
Prokaryotic cellular communication is similar, though the intracellular receiver is not an organelle.
Each cell type has its own language, appropriate to its lifestyle. Cell nomenclature also includes vocabulary that is understood by other cell types, including other organisms.
The energy economics of evolution practically dictate the forms that cell signaling take, though biochemical communications have evolved context: how a specific signal is to be interpreted.
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As all eukaryotes are symbiotic, different species being able to communicate at the cellular level is essential. Consensual communications often lead to concerted actions.
In humans, commensal bacteria help keep the body in pathogen-pounding condition. Bacterial signals influence immune cell training and warn of invasion. They even fight infectious agents. The reason they do so is self-interest: invading pathogens are competition for limited resources and can wreak havoc upon the shared homestead.
Intracellular Communication
“Inside the cell, there exists a network of molecules. Between them, information is constantly being exchanged.” ~ German microbiologist Ingo Schmitz
Every cell, whether a primordial yeast or post-modern human, has a complex high-speed system of pathways for transporting cargo within, such as proteins and various vesicles. Actin cables, formed into helical filaments, are protein-paved highways. Myosin molecules are nanoscale motor proteins that ply the filaments as transporters.
A cell’s transport network is highly optimized in paths and lengths: neither too long, nor coming up short. Every cell organically finesses a fiendishly difficult geometry problem. The problem is solved by feedback: passengers communicate to the cellular machinery providing the transport via protein tokens which regulate path growth.
Transport is just one facet of cellular communication. Intracellular chat transpires in numerous ways for a wide variety of functions related to every state and stage of a cell’s life.
Using peptides (protein fragments), status updates are regularly transmitted from deep within a cell to the cell’s surface, to keep the immune system and other interested parties informed about what is going on within the cell. (Peptide-loading complexes within the endoplasmic reticulum are responsible for production and quality control of messaging peptides.) At the cell surface, MHC-1 proteins filter the data in the status updates and present only relevant information to patrolling immune system cells.
(MHC-1 is a class of immune system related glycoproteins. MHC stands for major histocompatibility complex; a term referring to biological (tissue) compatibility. There are 3 MHC classes.)
Calcium Ion Channels
Calciumion (Ca2+) waves are a ubiquitous intracellular message medium that regulates diverse cellular activities. Besides intracellular signaling, extracellular environmental information is translated from calcium waves. The physiological correlate of cognition transpires via calcium waves traversing glia cells in the brains of animals and among plant cells. Certain proteins modulate the waves which other proteins receive and interpret.
Calcium wave communication is like music in that the intensity and frequency of waves – the distinct pattern – determines the message.
It’s like in an orchestra, where studying an isolated note on its own allows no inference of the melody. You have to hear how the frequency and volume of all instruments vary and produce the melody. Then you gain an impression of the musical piece.
“At first sight, there is no simple pattern to the ion impulses. Yet they still culminate in a meaningful response inside the cell. The pattern is the actual signal that leads to a response in the cells.” ~ Luxembourger biologist Alexander Skupin
Electrons
“Electrons are the fuel.” ~ Chinese molecular biologist Chang-Jun Liu
Calcium ion waves illustrate the modus operandi of communication at the most basic physical level: the deliberate movement of electrons.
Proteinsspecify construction of cellular materials by precisely placing electrons. For instance, plant cell proteins selectively allocate electrons at just the right time to produce the specific type of lignin that a plant wants. Lignin is the complex polymer that provides the scaffolding for algae and plant cells.
Salmonellabacteria are intracellular pathogens. They ply their infectious trade by shuffling electrons.
To spread their infection, Salmonella hitch rides in macrophages, which are immune system cells responsible for containing infection. First, a bacterium calls for a taxi by generating an electric field which attracts white blood cells. Macrophagesengulf the electrified Salmonella, supposedly succeeding in pathogen containment.
Once ensconced in a while blood cell, a Salmonella changes its electronic songs to get the macrophage to leave the intestinal tissue where the cell made its capture. The macrophage enters the circulatory system carrying its captive. The Salmonella then entices its release with an electronic signal, thus allowing the infection to spread through the body. A wily symphony of electrons has macrophages dancing like puppets to Salmonella’s tune.
ProkaryotePalindromes
To protect themselves against chemical threats, many prokaryotes, including bacteria and archaea, employ a toxin-antitoxin (TA) system. A TA system is a set of 2 or more linked genes which together encode for both a toxin protein and a corresponding antitoxin. A TA system allows for recognition (of a toxin) and remedy (by applying the antitoxin).
There are 6 known toxin-antitoxin systems, which are classified by the physical medium the antitoxin uses to neutralize the toxin. RNA is used in types 1 and 3. The type 2 system inhibits a toxic protein by binding an antitoxin protein to it, imprisoning the toxin. Types 4–6 are less common than the first 3.
Bacteria are fond of type 2 TA. The genetic information to implement this system can be tucked into a plasmid (a tiny capsule) and shared with others – horizontal gene transfer. This helps bacterial colonies survive what would otherwise be a lethal onslaught.
A palindrome is a word that reads the same forward or backward. Civic is an exemplary palindrome.
In over 25% of known bacteria species, the instructions that tell type 2 antitoxin proteins how to do their job are encoded as palindromes. Archaea also use TA palindromes.
The especial advantage of palindromes is robustness. A portion of a palindrome may be damaged yet still be decipherable by knowing that the message is a palindrome. The coherence behind evolution can be quite the clever packager.
Intercellular Communication
“All cells use information about the forces in their environments to direct decisions about migration, division, and cell fate.” ~ American cytologist Douglas Robinson
Cells live by intelligence. This requires interactive communication.
There are ~200 different cell types in the 37.2 trillion cells in a human body. Most cells express dozens, or even hundreds, of distinct cell messenger molecules (ligands) and receptors – creating a highly-interconnected network of cell types which intercommunicate through multiple ligand-receptor pathways.
Cells speak only a handful of different molecular languages to work together to carry out an incredible diversity of tasks. These languages are sophisticated and have a large vocabulary. ~ American biologist Michael Elowitz
As a plant grows, each cell needs to know its place in relation to other cells. Cells communicate to create the patterns from which different tissues arise. Plants do so using small bits of RNA, which is a particularly rich information medium.
Unlike conventional development signals, small RNAs operate in a highly specific way, and they can intervene directly in gene activity. ~ German plant geneticist Marja Timmermans
Besides monitoring internal operations, cells constantly acquire information about their external environment. This information is critical to making informed decisions about processes essential to survival, growth, and reproduction.
Age mosaicism across multiple scales is a fundamental principle of adult tissue, cell, and protein complex organization.
~ American cytologist Martin Hetzer et al
Organs and cells comprise constituent components at different ages. Every organ is a mix of old and new cells. Every cell has novice and experienced proteins. The reason is educational: for youngsters to learn from their elders how the show is run.
Sweet Talk
“Telltale surface sugars enable cells to identify and interact with one another.” ~ Israeli biochemists Nathan Sharon& Halina Lis
All cells wear a coat of sugar molecules (glycans) as part of surface glycoproteins. Glycans stick out like an antennae forest. Glycans can cluster and thereby channel water over a surprisingly large range: tens of nanometers (a water molecule is a mere 0.3 nm). By this, sugar facilitates communication through intercellular fluid.
Stem Cell Conference
Stem cells are the mother of all eukaryotic cells: generics that can differentiate into specialized cells to perform specific functions. Stem cells can also self-renew and generate more stem cells.
Early in an organism’s life, following a development plan, embryonic stem cells differentiate into cells that form various tissues and organs. This process comes from exquisitely coordinated dialogues between cells. At least 3 different protein networks are involved in stem cell differentiation.
1st, activating and deactivating various genes direct a stem cell toward differentiation. This involves a flurry of epigenetic intracellular communication.
2nd, epigenetic tags on messenger RNA of activated genes properly nudge a cell toward differentiation.
3rd, the feedback loop that normally inhibits cell proliferation is blocked, allowing rapid cellular development in the determined direction. Cancer cells proliferate by blocking this inhibiting feedback loop.
Epigenetics provides both the language and recordkeeping of what is going on during this complex conference, which eventuates in a stem cell taking on a new role.
As needed throughout life, stem cells provide repairs by replacing damaged cells. The communication process involved is selfsame to that during development.
Wounds
“Epithelial wound healing is a multistage process. Cells must detect the presence of a wound, migrate and proliferate in a coordinated fashion to close the defect, and then successfully reestablish tissue-wide epithelial architecture.” ~ American cytologist Erica Shannon et al
One way that damaged and dying animal cells communicate their distress is by releasing specific proteins into the extracellular fluid. Another way is through specialized intercellular tactile connections. These junctions allow neighbors to directly exchange electrical impulses, ions, and molecules.
Other cells pick up on these signals and boost their internal calcium levels, triggering a transformation from static to mobile form, allowing undamaged cells to initiate wound repair.
Communal Encyclopedia
“Biological production of extracellular vesicles is widespread, with vesicles produced by species across all branches of the tree of life.” ~ English marine microbiologist David Scanlan
Cells in all domains of life produce membraned vesicles(MVs) that contain lipids, proteins, and genic information. These vesicles are constantly secreted into the surrounding environment. MV production and secretion is dynamic and manipulatable, allowing cells to send informational messages and receive feedback.
Exosomes are saucer shaped MVs produced by most eukaryotic cells. All kinds of cells, including cancer cells, communicate over long distances using exosomes.
By their ubiquity, MVs provide a communal encyclopedia. Cells selectively incorporate encountered vesicles to ascertain a wealth of information about the neighborhood in which they live and its history.
This knowledge is especially helpful to microbes, which often traverse new territory. The genetic data in vesicles is especially useful as it affords transfer of nifty adaptations which may be incorporated and employed accordingly.
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Cells constantly adjust their metabolism based upon available nutrients. They regulate their repairs and transitions through the cell life cyclebased upon accessible supplies, requisitioning specific compounds through the cellular communication network as needed.
In a multicellular context, individual cells transform, reproduce, or even commit programmed suicide (apoptosis), to benefit the survival prospects of the whole organism. Dying cells interact with their neighbors, apprising them of their situation. They can send signals for other cells to proliferate and tell cells from afar that it is time for them to die too.
During development, certain cells must surrender their lives to advance an organism to the next stage. Fingers emerge from paddle-shaped hands by apoptosis of the cells that form the webbing between digits-to-be. Such self-sacrifice is the ultimate expression of intercellular cooperation.
“Cell-to-cell communication plays critical roles in specifying cell fate and coordinating development in all multicellular organisms.” ~ Chinese molecular biologist XianfengMorgan Xu
Primary Cilia
A ciliumis a slender protuberance projecting from a eukaryotic cell body. There are 2 types of cilia: motile and primary (non-motile).
Motile cilia are like the flagella on bacteria and some eukaryotic cells: a means of moving about. Sperm cells have motile cilium that lets them swim to their target and consummate a love connection.
A bacterium’s flagellumis a single lash-like tail that propels a bacterium through a fluid. A bacterium also uses its flagellum as a sensory organelle. Some bacteria, like Helicobacter pylori, which lives in the stomach, have multiple flagella.
Primary cilia are found in most animal cells. They were discovered in 1867 by Russian biologist Alexander Kovalevsky. Quickly dismissed as an evolutionary artifact of no significance, primary cilia were ignored for over a century.
The primary cilium is a cell’s transceiver: detecting a wealth of information about its surroundings and acting as a cell status transmitter. The primary cilium picks up protein-based chemical signals and information from mechanical forces, such as fluid flow and tensile force, in the immediate vicinity.
Cell status sent via primary cilium is essential to development and tissue maintenance, allowing coordination that otherwise would not happen. Primary cilia help orient stem cells in their direction of growth. Diseases result if primary cell cilia are not working properly.
For efficiency, there is only 1 primary cilium per cell. Multiple cilia would degrade signal reception quality as well as increase cellular complexity without advantage.
CommunicationLines
Cells constantly communicate with each other by direct contact (juxtacrine signaling), over short distances (paracrine signaling), and long distances (endocrine signaling).
Direct communication between adjacent cells underlies tissue organization. Contact signals use a simple sugar (oligosaccharide), protein, or lipid component of the cell membrane to message.
Nerve cells are juxtacrine signalers: translating internal electric pulses into chemical communiqués that are passed cell-to-cell over gap junctions. These conversations are overheard by nearby cells.
Brain stem cells monitor activity, listening in on nearby nerve and glia cells. This chemical eavesdropping regulates new cell growth.
Paracrine signals are used for cell growth and repair, including blood clotting and scar tissue formation. Allergen responses are initiated by paracrine signals.
Insects and crustaceans control growth through paracrine signals: allatostatins, which are neuropeptide hormones. Retinoic acid, the active form of vitamin A, is an allatostatin which regulates gene expression during embryonic development in higher animals.
Short-distance statements are typically designed to degrade quickly, as diffusion could lead to disruption rather than appropriate action.
Long-distance communication is big business in a multicellular organism; the medium to living large.
Neurons communicate over long distances via long fibers – axons – that send electrical signals. These cells provide the intelligence network known as the nervous system.
Other cells have cellular extensions – filopodia – which are used for sensing, cell-to-cell interactions, and migration. Cytonemes are long, thin filipodia that are specialized for exchanging signaling proteins between cells over long distances. Filopodia form a dedicated network by directly extending from cells that receive signaling proteins to cells that make them. Physical connection between cytonemes completes a private communication channel between cells.
The endocrine system is the glandular network. Glands produce hormones that traverse the bloodstream with regulation instructions.
Hormone is a general term for any endocrine signaling compound. All multicellular organisms produce hormones. Plant hormones are termed phytohormones. Animals typically transport hormones in the blood.
A hormone hits home on a certain cell receptor by binding to its receptor protein. This reception is then translated into cell-speak by a 2nd messenger. The cell then decides on an internal response.
In contrast to the glands of the endocrine system, exocrine glands are doers, not talkers: secreting their products exclusively through dedicated ducts directly into the external environment. Saliva, sweat, mucus, and mammary are mammal exocrine glands.
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Killer Diagrams
All animals have protection against the pathogens to which they are susceptible via an innate immune system.
Evolution upped the defensive game for vertebrates, which have an adaptive immune system that can learn and remember attacks to better cope the next time around. Innate immune systems also possess some memory, but it is not as sophisticated as in the adaptive variety.
Taking out the opposition is a team sport. Different cell classes and types are tasked with different roles and responsibilities.
For instance, there are 4 functional types of T cells, which play different roles: hunting (killers), assisting (helpers), not overdoing it (regulators), and archiving the episode (historians).
Killer T’s hunt in small packs. They converse as they prowl, expressing themselves by placing specific proteins on their surfaces.
T talk is tactile. T cells rub up against one another, placing new proteins into the interface between them. These protein paintings are organized into beautiful patterns. One looks like a bullseye. The spacing of the patterns is significant, as is the rigidity of the cell surface on which painting is done. T cells indulge in artful con-versation before terminating pathogens with extreme prejudice.
Cancer Cells
Cells must sense extracellular signals and transfer the information contained about their environment reliably to make appropriate decisions. ~ English biologist Margaritis Voliotiset al
Cell sickness is characterized by a cell dropping social communication; leaving various feedback loops unanswered. Cancer cells arise this way: following their own inner voice while ignoring orders to cease and desist. Then, as a cellular sociopath, cancer turns intercellular communication to its own ends.
Cancer starts in one tissue before it spreads to certain types of secondary tissue. The mystery of metastasis lies in communication. Cancer cells decide secondary infection by trying to start a conversation with new tissues. Those that answer are invaded. By this, breast cancer makes its way into bone.
Media
“The features of our face are hardly more than gestures which force of habit has made permanent.” ~ French writer Marcel Proust
Communication mediums vary, from molecular connections to waves of light, mechanical vibration/sound, and electricity. Every physical media that can convey information is a conduit for communication for some form of life.
Chemical transactions are the mainstay of every organism, and so chemical communiqués predominate as the most common medium; used by every life, both within and without.
Electricity is another intra- and intercellular communication medium, particularly well-suited for rapid transmission over distance; hence, selected for nerve signals. Electric communication between animals is rare. Electric fish employ various voltage vocalizations: short, abrupt zaps for aggressive encounters, but softer rasps during courtship.
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Communication modalities between life forms evolved in the context of habitat, as did every other aspect of an entity’s existence. 3 facets pertain: 1) what travels best in the environment between sender and receiver; 2) what delivers a relatively robust signal for the receiver’s senses; 3) the extent to which the interests of the sender and receiver coincide.
There is convergence between how an organism earns its keep and how it communicates. Animals that rely on vision for foraging and predation tend to communicate via visuals, and so on. Contrastingly, subterranean termites, for whom sight would be literally senseless, communicate by scent and touch, the same way they sustain themselves.
Light
The availability of a medium is a crucial factor. Visionmost often depends on daylight. The Moon at its brightest is 1/10th that of daylight. Some find workarounds.
Fireflies Alight
Firefliesand glowwormsmanufacture their own light and use it for signaling. Whereas a glow worm may shine from the sheer optimism of being a grub, fireflies put on a serious love light.
In the milky twilight of mild summer nights, a male firefly flashes his wares for females, who are a bit wary. A female responds only to those displays of light that she feels are right.
After a lengthy back-and-forth courtship on the blink, the lights go out. The flashy dating turns into an all-night mating.
The next night, a female is likely to mate again, with a different male; likewise for a beaming male. Fireflies like variety in their couplings for good reason.
A male gives his briefly betrothed a spermatophore: a sperm packet, which the female may later choose to use to impregnate herself. Packet size varies, and size matters. A male with a weighty wad gets the nod to father the next generation.
Mating is not the only reason fireflies alight. A firefly’s glow also warns off bats, which might otherwise eat them. It’s an honest signal. Bats think fireflies have a disgusting taste and will spit them out if they catch one.
Bats don’t depend solely on bioluminescence to avoid an unpalatable snack. Bats can tell fireflies apart from other insects by the speed at which fireflies beat their wings.
Bioluminescence
90% of deep-sea marine life produce bioluminescence. Humboldt squid flash patterns of colored bioluminescent lights to communicate with conspecifics using a sophisticated language.
Visual signaling is affected by both the amount of available light, and how well certain wavelengths travel. Blue light (475 nm wavelength) travels well through seawater but longer (infrared) and shorter (ultraviolet) wavelengths get filtered out. Hence, many reef fish are blue or yellow, or have striking stripes.
Watases lanternfishare hunted by predators that strike from below. Light-sensing cells around their bodies provide the essential information for ventral (downward-pointing) bioluminescent cells to make the lanternfish invisible to those looking up. Likewise, some squid employ bioluminescent bacteria for counter-illumination, to match the overhead environmental light as seen from below.
Some sea creatures, such as the black dragonfish, prevent being exposed by bioluminescence by sporting light-absorbing skin which renders them pitch black. A thin film that covers their skin comprises an intricate, layered matrix of microscopic granules that create a labyrinth for light.
“The trick to being really dark is to control the scattering of light. You have to let light into a material and let it bounce around a lot.” ~ American zoologist Sönke Johnsen
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Even on land, certain wavelengths travel better, and certain colorations are more conspicuous.
Leaf warblersare small arboreal birds with simple songs and various colorations depending upon where they live. Several have their niches in the trees. Whereas some prefer the top canopy, others nestle under shrubs. To optimize visual signaling, birds that live in darker habitats are more brightly colored.
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Colors in plants and animals are produced by pigments and nanostructures. Surprisingly, given the vast diversity of colors in fauna, animals lack many pigment synthesis genes that are common in plants. The evolution and employment of visual signaling through patterning and coloration is not understood.
We lack an appreciation of the developmental processes involved in cellular structures and pattern formation at optical scales. ~ English biologist Innes Cuthill et al in 2017
Given enough light, visual signals provide a vast diversity of possibilities. Like sound, visual signals are readily switched off or on.
Unlike sound, light does not go around corners. But the line-of-sight limitation is not necessarily bad, as it can prevent a predator or rival from catching on.
Patterns and colorations accentuate gestures, but gestures alone are good enough if the intended receiver is receptive.
Male jumping spiders wave their front limbs in species-specific semaphores to females. Fiddler crabs jerk their one enlarged claw in rhythms that other fiddlers comprehend.
Facial expressions are commonly used among mammals. Visual communications may be even more subtle. Among wolves and many ungulates, eyes and/or ears alone convey messages that conspecifics understand.
Visual signals that work over a broad range of frequencies are best for long distances. White contrasted against any dark offset is very conspicuous at every remove – hence the white tails of rabbits and deer, and the dashing eyebrows of mangabey monkeys.
Sound
Animals make sounds that vary by motivational state. Aggression is signaled by a low frequency growl, while the sound of fear is high-pitched. The sound of a dog barking at a stranger approaching shows how the 2 emotions may be combined into a distinct sound signature.
Sound is more subject to degradation than light, though high frequency sounds attenuate and are scattered by obstacles more readily than low frequencies, regardless of environ. Some creatures take advantage of these audio parameters to tailor their sonic signals.
Habitat fosters speciation, and communication factors in. Urban birds, such as sparrows and tits, sing louder and at a higher pitch than their country cousins. They do so to be heard over the noise. They also make other spectral changes in their songs, including timing, to improve conveyance.
Echolocation
“Echolocating bats have superfast muscles which are rare in vertebrates and always associated with extraordinary motor demands on acoustic communication.” ~ Danish zoologist Coen Elemans et al
Around 70% of batspecies feed on small insects. Most forage on the fly via echolocation: ultrasonic sounds specifically emitted to produce echoes which a bat hears and processes to get precise mental images of local terrain, and of prey. Bats recognize the individual signature of their calls – a exquisitely fine discrimination amid a group of selfsame bats. Bats prefer hunting amid vegetation that helps amplify their calls.
Echolocation also acts as a communication medium. Big brown bats are insectivorous aerial hawkers that forage near others. Individuals emit calls to those nearby to claim dibs on flying morsels of choice. Competition for food can be so intense that bats actively jam the echolocation of other bats, effectively foiling their closing in on prey.
Bat biosonar is a most energetic animal sound: up to a roaring 140 decibels. When emitting a call – to avoid deafening themselves – bats stop up their hearing by contracting their middle ear muscles. Their ear muscles relax in time to receive an echo.
Certain bats can deform the shapes of their ears in a way that changes the animal’s ultrasonic hearing pattern. Within just 1/10th of a second, these bats are able to change their outer ear shapes from one extreme configuration to another. ~ German biologist Rolf Müller
A large object rather readily produces an echo at low energy and wavelength. Sussing out small objects requires finer resolving power. Hence bats need high frequency: 50–100 kHz. Because sounds travel faster in water than air, dolphins employ echolocation up to 300 kHz.
The echolocation muscles that bats use to hone in on a flying insect, dubbed terminal buzz, are superfast: 100 times faster than typical body muscles, and 20 times faster than the fastest human muscles, which control eye movement. The sound-producing muscles of rattlesnakes, birds, and several fish species are superfast.
Ultrasonic is an anthropocentric term: sound frequency above human hearing. Human hearing hangs up at 20 kHz (at best).
A bat emits 2 spectra of sound frequencies – one high, one low – into a wide cone of space ahead of it. Within the spectra are harmonic pairs of high and low frequencies.
The farther away or more peripheral a reflecting object is, the weaker the higher frequency reflection in the harmonic pair. Objects that reflect harmonic pairs back in perfect synchrony are the ones that stand out clearly for the bat.
Bat sensation converts the difference in signal strength into a delay in time (about 15 microseconds per decibel) so that harmonic pairs with wide differences in signal strength end up being perceived as out of synchrony in time. Objects with these out-of-sync signals are perceived as background, while front-and-center objects that reflect back both harmonics with equal strength rise above their desynchronized competitors.
A 100-kHz bat call drops to 1/50,000 of its emitted intensity 4–5 centimeters away. Bats separate their calls in frequency and time to optimize echolocation, as well as varying the intensity and width of sonar waves, as ways of varying the locus of attention.
Though the medium is sound, bats essentially see via echolocation. In constructing mental images, bats account for Doppler shift: the change in wavelength because of relative movement.
Echolocation is a physics-challenging adaptation but is the only possibility for night-flight hunting given the parameters of the prey.
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Sound is a tricky medium. Low frequencies travel farther, though lack the precision of shorter wavelengths.
Male green tree frogs use a dual-frequency call. A female picks up the lower frequency at a distance. As she approaches the male, the higher frequency component kicks in.
Elevation helps. Cricket chirps from shrubs or trees travel 14 times farther than those sung from the ground, resulting in a better female draw. Territorial bird songs are typically delivered from an elevated post, enhancing effective range. Territorial grassland birds, such as meadowlarks and pipits, deliver their declaratory pips on the fly.
There is less attenuation of sound in water than air, partly because sound in water travels faster, and water is a more stable momentary medium. Hence many aquatic animals extensively communicate by sound.
The benthos off Los Angeles is an acoustic cacophony: shrimp, lobsters, crabs, and fish snapping, rasping, humming, squeaking, and grunting. California mantis shrimp reside there on the ocean floor; burrow-dwellers in muddy water. Each shrimp has its own recognizable voice. By muscle vibration, males sing in a 3-part low frequency harmonic rhythmic rumble to attract females to their lovely burrow, or to defend territory.
Birdwarning calls illustrate how precision can matter. The source of an alarm call should be difficult for the predator to locate. To achieve this, several facets apply.
The call should gradually fade in and out. It should be a thin, pure tone, optimally pitched at a frequency determined by the distance between the predator’s ears.
For a mid-sized hawk or owl, 7 kilohertz makes it perfectly vexing for these birds of prey to locate the sound source. This matches the actual alarm call used by several small bird species to warn of an approaching aerial predator. Thus, prey alarms blend with the predator’s own vocalizations, and so are not as distinctive as they would be if at a different frequency.
Whalesongs can be heard for hundreds of miles, but distance is not everything. Whales are good listeners and adjust their singing to local conditions to optimize the quality of reception, not just range.
Electrical
Intracellular communication relies heavily upon electric charges. Nerve cells employ a combination of electrical and chemical communication. The electrical portion is used for rapid, long-distance signaling, whereas the chemical is up-close and intercellular.
Little is known about electric field communication between organisms. Bacteria use electric currents to forage and communicate. Electric fish chat via electric fields.
Beesacquire a positive charge of up to 200 volts as they fly through the air. Flowers emit weak negatively charged electric fields which an approaching bee can detect.
When a bee lands on a flower, the floral field changes, altering the electrical potential for several minutes. This lets another bee know that the flower has already been visited.
Electric eelsare powerful persuaders. They emit high-voltage zaps through the water as a hunting probe. The electric shock causes involuntary muscle twitches in nearby prey, which reveals to the eel the prey’s presence.
Upon such a finding, an electric eel approaches and turns up the wattage. Within 3 milliseconds, the prey is stunned into joining the eel for supper, as the main course.
Cuttlefish, squid, and octopi can consciously change their coloration in milliseconds, rapidly recloaking when facing danger. Cuttlefish can also freeze their movements, greatly reducing their ventilation rate and electrical output. This diminishes the risk of a shark being able to detect them. Sharks are sensitive to electric pulses at close range.
Chemical
“Communication via chemical means appears to be the oldest and most widespread mode of signaling among animals.” ~ American biologist Kevin Theis et al
Chemistry is the universal language of life. Microbes earn their living as chemists.
In contrast, conscious sense of smell in humansis slight compared to its unconscious perception. Conscious human communication is dominated by sight and sound, with the world becoming tangible via the sense of touch.
For most species, chemo-communication is common, and is a communication channel notably well-developed in insects and mammals. Caste-bound eusocial ants maintain massive colonies using sophisticated communication systems via ~20 different pheromones.
Just as 2 ears and 2 eyes aid perceptiveness in hearing and sight respectively, so too 2 nostrils afford keener olfaction. Locating objects is much easier with stereo inputs, as differential in signal strength determines direction.
Duration is one facet of chemical communication. Some chemical signals are designed to last only a short time. For that, volatile compounds with low molecular weight are employed.
Ant pheromone alarms – to signal others of impending danger – are detectable only within 3–5 meters, and usually fade within a minute or less. If not so, it would be impossible to localize the threat.
Azteca Ants & Phorid Flies
Short-lived antalarms can create a cascade.
Azteca instabiliscra are large forest ants that nest in the hollow trunks of trees. Nowadays they patrol coffee bushes; having hitched rides to inhabit every coffee-growing nation.
Azteca ants enjoy a mutualistic relationship with the green scale, which feeds off plants, including coffee. The green scale’s appetite for coffee plants earned them the name green coffee scale, and the enmity of coffee growers as a pest.
Azteca ants protect the green scale from predators and parasites, though coffee growers are simply beyond control. The green scale provides payback by secreting a sticky, sweet honeydew for the ants.
Lady beetlesdine on green scales when they can get past bodyguard ants. Patrolling ants attack and kill adult beetles, as well as removing lady beetle eggs laid on ant-tended coffee plants.
Azteca ants are afflicted by phorid flies; a family of tiny humpbacked flies that resemble fruit flies. The best-known phoridis the coffin fly: famed for a fondness for human corpses. The world teeniest fly is a 0.4 mm phorid.
Phorids attack Azteca ants by laying eggs on the ant. When the eggs hatch, larvae make their way to the ant’s head, which feast on ant brain. The ant’s head falls off when the adult flies emerge.
Phorids stalk their prey by detecting Azteca on the move. Stationary ants are not a target.
A phorid fly attack prompts an Azteca pheromone alarm, warning other workers in the vicinity. Nearby ants respond by becoming catatonic. Colony activity drops by at least 50% for up to 2 hours.
Pregnant lady beetles detect the ant alarm scent and take advantage of the lull by laying their eggs at safe sites that offer plenty of food for their offspring. In contrast, as it affords them no opportunity, male beetles do not care about Azteca ant calls, and so pay the calls no mind.
Nematodes & Fungi
Nematodesare one of the most abundant animals in the world. Roundworms communicate with each other via ascarosides, which are small signaling pheromones. This is an extension of nematode intercellular communication, which also employs ascarosides.
Nematodes are preyed upon by fungi, which build sticky webs to trap the worms. Building a web takes considerable effort. Fungi only rise to the occasion after eavesdropping on nearby worm talk, which signals that a catch may be made.
Moth Advertising
Volatile scents are employed in patterning signals. Some moths advertise sex-attractant pheromones in single-second pulses. But most mothpheromones strike a compromise between ease of dispersal and persistence. A male moth may catch the scent of a female 4–5 kilometers downwind. It is a short-lived pheromone with excellent dispersal.
Other chemical missives are meant to last. Moth territory markers tend to be persistent and carry a fairly high molecular weight, but not so high as to not stay airborne.
Hefty molecules are more difficult to synthesize, secret and spread. For moths, territory goes to those with stamina.
Benthic Scents
It’s not safe at the bottom of the sea. Seaweeds and sponges that attach to the seabed manufacture toxins to keep from being fish food. To avoid being bit, they emit chemical signals to alert those that would otherwise be tempted. That is an opportunity for other potential fish prey to share the signal.
Sea slugsare oceanic snails without shells. They have adapted to take advantage of the noxious benthic fodder, eating nothing but toxic seaweed and sequestering the toxins themselves.
As the toxins serve as adequate protection, shells were no longer necessary. Several sea slug species also sequester the chloroplasts that power the seaweed, turning themselves into leaves that crawl.
Fire coralare misnamed. They are colonial marine organisms that look like coral but are more closely related to jellyfish and stinging anemones. Their fire is a nematocyte: a barb with chemical sting. Fire coral employ chemistry to get a better, higher spot in the water column: chemically sensing an inferior competitor nearby, then selectively expanding toward the competitor, and eventually overgrowing it.
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For many species, chemical communications play a significant role in foraging for food, mating, and competitive interactions. While birds employ plumage, many mammals use scent to similar ends. The difference owes to distance. Whereas birds most easily signal afar by line-of-sight, mammals group in close proximity.
Most animals possess multiple modalities for communicating. The chosen form varies by immediate context. Mammals employ sight and hearing for messages to distant places, scent closer in, and tactile communication as the most intimate.
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As a social vehicle, chemistry is not just a communications medium. Chemical defense is common among all forms of life.
Stimuli
Communicationis only successful when the intended message is received. Most receptions straightforwardly match the signal sent. But how a message comes across can be quite different from the intent of the sender. Sometimes it is a case of bait-and-switch, or switch-from-being-bait.
A male jumping spiderfirst attracts the attention of a female not by looks, but how well he moves like food. A male’s best sparking way is to mimic tasty prey. A successful spider’s mating dance is an elaborate display: scraping sounds and buzzes, with an occasional rhythmic thump from the spider’s abdomen slapping the ground. Once a male has cajoled a female to come close, he changes his act: from potential prey to potential mate.
Water mitesare ambush predators: they lie in wait with their front legs in the air; a net stance to enhance the chance of grabbing a passing crustacean. As a mating prelude, a male approaches a female while vibrating his legs at 15 Hz: within the range of a crunchy copepod crustacean. A female grabs a vibrating male as she would a prey. The male, larger than any meal, is unhurt. As he starts spewing spermatophores nearby, the female realizes what is going on. She switches to sexual behavior and plucks a spermatophore for insemination.
A male Oriental fruit mothalso fools a female by imitating food, but here the signal is scent. A male first finds a female by her scent, but when close by, he wafts his own, which includes a pheromone that is also found in fermented fruit juices, which is the beverage of choice for Oriental fruit moths everywhere.
These examples of preliminary mating signals are communication substitution: signaling in a way that relies upon a strong disposition to pre-existing reception. The first rule of advertising is to get attention.
Noise
Noiseis a problem for all that encounter it. Whales subject to noise from ships are impaired in their communication.
In a long-running demonstration that “military intelligence” is an oxymoron, the US Navy has blasted the seas for decades with sonar assaults that discombobulate and kill marine mammals. Taken to court for the senseless killing, the American Supreme Court saw no problem with it.
Birdchicks in a noisy habitat are less likely to survive. The continual stress can be fatal.
Urban birds alter their songs and calls to be heard over traffic. Similarly, insects adjust their sound signals to surmount the sonic assault of city slickers.
A common technique to overcome noise is repetition. Many animals repeat calls in rapid succession. This helps the receiver confirm what it thought it heard.
Even cells are subject to noise. Living in tissue can be near-constant cacophony, so cellstune out distracting chatter to concentrate on the chemical communiqués that matter. They shift the molecular mix of signals to improve the odds of reception. When cells replicate, they pass their successful techniques on to the next generation.
Evolution of Communication
Communicationis an adaptive dance, its form evolving based upon antecedent employment. A natural tendency is reuse, modifying from an existing mechanism. Mating signals of water mites and fruit moths are recycles of a signal even stronger than the urge to reproduce: the need to eat.
A receiving channel must exist for a sending signal to have any chance. Receptiveness readies the prospect and practically dictates the type of signal used for communication.
Moths
Saturniid moths can’t hear. Down the evolutionary pike one stop, whistling moths hear well enough. The adaptation arose from a change in lifestyle.
Saturniid moths have the same receptors as whistling moths but they use them to align of body parts, to help adjust the moth’s spatial positioning.
There is a slight thinning of the cuticle over the receptors that changes the appreciation of internal vibrations in saturniid moths to the ability to hear in whistling moths. Male whistling moths rub their knobbed wings together to make a racket of loud ultrasonic pulses. Whistling moths use such signals to stake territory and attract females.
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The facility for dialogue rests upon a shared syntax: the patterning by which communication elements are understood. The physical and mental structures used for conspecific communication are innate. For example, humans are born with the basic syntactical knowledge upon which all their languages are based.
Mangrove Snapper
The mangrove snapperis a fish native to the western Atlantic Ocean. Throughout their lives, snapper use calls to keep their schools together.
Snapper life begins in open water. Sperm and eggs are broadcast in proximity. The fish are born adrift. Centimeter-long larvae are neither helpless nor witless. They growl and produce percussive knocks that let others know of their presence. This helps them traverse the ocean at night together.
Spotted Hyena
Hyenasare fierce carnivores. If the numbers are in their favor, they will steal a wildebeest kill right under the noses of a lion pride enjoying their victory feast.
Hyenas exhibit sexual dimorphism: an innate size difference between male and female. Whereas spotted hyena males are smaller than females, males in other hyena species are larger.
Hyenas are quite social, though with a strict clan hierarchy befitting their ferocity. Spotted hyena clan size varies but may number up to 80.
Even the lowest-ranking spotted hyena females rank above the alpha males. Spotted hyena females not only keep males in their place, they compete intensely among themselves for status. With social dominance comes feeding and breeding privileges that confer dramatic gains in reproductive success.
Alpha females always hunt within clan territory. If the pickings are slim, subordinate females may have to travel outside home hunting grounds for a meal; a risky endeavor.
The offspring of top females grow faster and are more likely to survive than subordinate hyenas. This puts them on track for dominance in the next generation.
Penises are quite something as a social signal. Spotted hyenas prefer sniffing a penis, even taking a lick upon occasion, to the more mundane whiffing of anal glands common among other mammal species, such as dogs and cats, to which the hyena is a distant relation.
Spotted hyena attention to penises applies to both genders. Spotted hyena females have pseudo-penises, which are much like male penises in look and behavior. An erect pseudo-penis is used between females to say hello, as it is with males.
The female pseudo-penis is fully functional: used for urination and copulation. The female pseudo-penis precludes the possibility of rape, as well as making mating more laborious for males.
Some other species, including the squirrel monkey, lemur, and bearcat, have pseudo-penises. Elongated labia occasionally appear in humans.
The biological cost of the pseudo-penis is considerable. The birth canal extends through the pseudo-penis, constricting the canal such that birth delivery (parturition), particularly of first-borns, often leads to fatal complications for both mother and pup. After parturition, the pseudo-penis is stretched out of shape, alleviating much of the danger of the next pup birth.
The microbiotic bacteria that live in hyenas make a pungent paste – hyena butter – in pouches situated next to a hyena’s anus. Butter quality is variable; an ideal honest signal.
Hyenas dab spots of the smelly paste on grass, giving conspecifics a wealth of information. Besides telling the time of the visit, hyena butter gives a medical status report, including sexual receptivity. As part of the butter, the microbes that once lived in hyenas are now on diplomatic duty, talking on behalf of their erstwhile host.
“Scent posts are bulletin boards, pastes are business cards, and bacteria are the ink, shaped into letters and words that provide information about the paster to the boards’ visitors. Without the ink, there is potentially just a board of blank, uninformative cards.” ~ Kevin Theis
Coinciding Interests
“Communication is the reason cooperation occurs.” ~ Flemish microbiologist Christoph Adami
The form of communication varies depending on the relation between sender and receiver. With coinciding interests comes sotto voce communication: soft signals, sometimes so inconspicuous as to be sharing a secret. Communication of convergence is seldom energetic.
The communication of potential conflict is typically of an entirely different nature: energetic, boisterous displays, sometimes leading to violence. But sometimes communication of conflicting interests comes down to a simple display.
When chased by a potential predator, gazelles and other ungulatesstotto show their strength. A stot is a certain gait of quadrupeds that involves jumping into the air.
Stotting is an advertisement of health. It slows an animal down from its regular running stride, and thus potentially increases the odds of being caught, but it honestly signals that an animal is strong.
Stotting works. Gazelle hunters, such as African wild dogs and cheetahs, discriminate based on stotting rate, concentrating on spotty stotters who may be more easily caught.
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African wild dogsare especially savvy predators. They hunt in packs, using vocalizations for ad-hoc coordination. This lets them bring down larger and faster prey than they could otherwise.
The cheetahis known for its speed, but it does not just rely upon quickness to run down its prey. Cheetahs anticipate the escape tactics of their specific quarry. Agility is as important as speed in bringing prey down.
While the cheetah is absolutely the fastest land animal, the animal quickest in relative terms is the tiny miteParatarsotomus smacropalpis (0.5 mm), which can move 322 body lengths per second compared to the cheetah’s measly 16.
Feeding Offspring
Many species care for their young to considerable effort. Conflicts commonly arise in a family over resources.
Each offspring demands food at the expense of its siblings. Parents decide how to allocate limited food by determining which offspring are in greatest need.
There are numerous beggingsignals in various species. Therein lies an opportunity for deception: a youngling may signal a greater hunger than it really has. Nature sometimes does not permit such deceit.
Young canarieshave a conspicuous and honest begging signal: a mouth gape with a red lining; the red lining from a suffusion of blood near the surface. A parent puts food in the reddest mouth it can find among its young.
When a chick has eaten, its mouth lining pales, as blood is transferred to aid digestion. So, redness of mouth is an honest signal of hunger. Canary parents that allocate food on that signal have the best chance of rearing the most chicks.
Recognition
Relationships between organisms require that individuals recognize one another. Such recognition is common even in early-evolved life.
At the cellular level, virusesknow exactly where they are going. Among the variety of cell types, a virus recognizes its specific target. A virus makes its way via discrete inquiries with other cell types.
Plants recognize siblings with whom they share soil.
Social animals have especial need to recognize one another. Individuals are important where relationships exist for any duration, especially in any community with a social hierarchy.
The dark paper wasp, native to North America, is best known for making its paper nests below the roofs of houses (or in trees or foliage). A female founds her own colony. She’s no good at recognizing faces.
But her close cousin – the golden paper wasp – is. Goldie females form group colonies: building a joint nest and laying eggs there. Clustering queens squabble and determine a dominance hierarchy. So, it comes as no surprise that golden paper wasps, and other social wasps, remember and recognize individual faces; even human faces. While rigid exoskeletons disallow facial expressions, wasp heads do have different shapes, sizes, and features.
Birds recognize one another. Among a colony that can number up to half a million members, mated penguin partners find each other.
Ravens not only recognize each other, they long remember their affinity in individual relationships, even after being separated for years.
Practically all social mammals recognize each other individually. How they do so is sometimes surprising. Bats recognize one another by their echolocation calls, which have signature individuality.
Kinship
“Kinship is a basic organizing principle of all societies.” ~ American biologists David Pfennig& Paul Sherman
Sociality begins with family. All kinds of plants and animals know their kin.
Plants typically grow faster in the presence of relations than among strangers. Chemical cues released by roots let relatives recognize one another.
Almost all animals know their relations. Sea squirts lack an identifiable brain but know when they encounter kin.
Western toad tadpoles school with siblings. They also know the smell of their natal home.
Sage Rats
The sage rat is a ground squirrelthat lives in the mountains of the western United States. Adult males are nomadic.
The ladies run a nepotistic society. Females can tell a sister from a half-sister by their individual funky fumes. The level of cooperation one female might expect from another depends upon how closely related they are.
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Recognizing relatives is an essential aspect of sexual reproduction, the point of which is to engender genetic diversity, to raise the probability that some individuals survive when others in a population may not. When it comes to sex, kin recognition prevents inbreeding, which is a biological taboo of both plants and animals.
Sociality presents a different context. Being conscious of clan cultures camaraderie. Shared heredity give rise to common cause. The basis for cooperative behaviors of every kind come from kin recognition.
It is a tiny leap in the mind of an organism to translate biology into the broader frame of association called attraction. Kinship is only one side of the coin of comity.
The flip side is mating. Promoting genetic diversity requires accepting outsiders and making them family, for at least some duration.
Hence, all sociality has a genetic genesis which translates into innate behaviors and mental constructs. From cooperation to war, biology brackets all social expressions.
Status Sniff
Many mammals, including dogs, rats, and cats, sniff each other out when they meet. For rodents at least, sniffing intensity signals social status.
Subordinates stifle sniffing in the face of a dominant rodent or risk its wrath. Snuffing sniffing is an appeasement signal. Such sniffing has nothing to do with smell. Instead, the behavior itself signals subordination.
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Coinciding interests can sometimes be quite smelly, and costly. Lacking a way to get around, yeastneed a ride. To grab a cab, brewer’s yeast produce fruity aromas that attract fruit flies. Alas, the ticket to ride is a sacrifice gambit. Some yeast become lunch. But enough get attached to these nomadic flies and survive to travel to the ripe and rotting fruit that both yeast and fly prefer.
Audience Effect
Many animals live in a communication network, an environment where individuals can obtain information about competitors or potential mates by observing interactions between conspecifics. In such an environment, interactants might benefit by changing their signaling behaviour in the presence of an audience. ~ French ethologist Davy Ung et al
For social animals, eavesdropping provides valuable information about conspecifics. Many animals behave differently when they know they are being watched. This is the audience effect.
Male vervet monkeys, especially subordinate males, alter their behavior toward infants depending upon the perceived presence or absence of the mother. Correspondingly, a mother’s attitude is affected by a male’s behavior toward her infant, and his social status.
Fornicating female chimps modulate their cries of enjoyment depending upon who may be listening. Subordinates particularly pipe down if a higher-ranking female may be within earshot.
Adroitness commonly determines a male’s mating prospects. Field crickets and guppies become more aggressive in male-male competitions when a female is present.
Siamese fighting fishare territorial, and naturally aggressive – both male and female. They try to intimidate one another by flaring their gill covers to appear more impressive. Both sexes establish respective dominance hierarchies in their communities. In doing so, some fighting is spared by fish spectating conflicts between conspecifics. An observer can tell rivals’ skills, and its own chances, by watching combatants, and then act accordingly. Male-male contests set both social status and mating chances. Females watch combatants and flirt with the winners.
Nightingalesare known for the beauty of their powerfully sung songs. These tunes are advertisements of prowess, for both mating and dominance among these territorial birds. Dyadic contests are common, with one bird overlapping the song of another. While the rivalry is intended to affect an adversary, such performances also influence the future interactions of conspecifics who eavesdrop on competitive concerts.
Canariesare socially monogamous but engage in extra-pair copulations if the opportunity arises. Females eavesdrop on vocal and physical contests between males and use that information to direct their sexual behaviors. A female who sees her mate fare poorly in a contest with another male is more given to sex with males other than her mate; discreetly, of course.
Male canaries adjust their behaviors based upon who is watching, and what their social bond is with the onlooker. A male will not flirt with another female if his wife might see him do so. Similarly, male canaries adjust their agonistic antics toward each other depending upon the audience.
Honesty
“Honesty is the best policy.” ~ English Anglican bishop Edwin Sandys
Combat between contestants for territory or mating rights is seldom fatal, and frequently not even physical. Ritualized threat displays commonly settle a matter.
When dominance determination does get physical, it is often brief and without severe injury. In sparing substantial wear and tear, such assessments are biological efficiencies.
To fight and conquer in all your battles is not supreme excellence. Supreme excellence consists in breaking the enemy’s resistance without fighting. ~ Chinese military general, strategist, and philosopher Sun Tzuin The Art of War (6th century BCE)
Roaring Deer
Male red deer contend for female mating privilege, beginning with loud roars as an indication of fighting ability. Once out-called, a stag will sometimes withdraw without further ado. If not, roaring escalates, increasingly faster and fiercer. If one is not out-roared, fighting is likely.
Roaring is an honest indicator of power. Only a healthy, powerful buck can sustain a rage of roaring. Several deer species rely upon this same mating mechanism.
If roaring doesn’t end a red deer contest, push comes to shove. Male red deer lock horns and push each other a bit, whereupon one concedes defeat.
Antlers & Horns
Reindeer stags have magnificent antlers, topped only by moose in splendor. Ostensibly the antlers of reindeer and moose afford battle weapons for mating. Only rarely do the antlers actually encounter combat, and then for but the briefest spar, antler to antler.
Most often 2 males assess each other’s antlers. The 2 never touch. The one with the inferior headdress declines battle. Which is to say that a moose or reindeer has a mental image of how his antlers compare to another. How such self-assessment is made is not known.
Australian antlered flies confront each other head to head for determination of rank. The fly with the ample antlers almost always wins.
Rhinoceros beetles wield a forked horn on their heads. Horn size is highly variable: ranging from itty bitty bumps to a horn o’ plenty that runs 2/3rds the length of a male’s body. In any mating contest, the male with the bigger horn gets to mate.
Positive Polarization
The vivid plumage of a peacockseduces a peafowl to mate with him. The wondrous sight owes largely to polarized light. Such splendor cannot be faked.
(The iridescent optics of peacock feathers is not the only allure. Peacocks quiver their tails during mating season, emitting low frequency sonics which appeal to peafowl.)
Nor with swordtailfish. Female swordtails have a decided preference for males with certain polarized patterns on their bodies. The more polarization a male swordtail has, the better its mating prospects.
Similarly, jeweled beetlesshimmer via iridescence on their elytra (hardened forewings). Females find the appeal of polarization irresistible.
Bull Elephant Seals
Only dominant bull elephant sealshave the privilege of breeding. A contender bellows for a shot at the title. A dominant bull answers back with a roar.
That may be enough persuasion. If not, a body slam or 2 settles the bout for a subordinate looking to step up for sex. The subordinate lumbers off down the beach as fast as it can, the victor bellowing in noisy but harmless pursuit, mostly as advertisement for other younger bulls with the same idea.
A dominant bull being displaced takes more persuasion. Contests resulting in overthrow get bloody and can even be fatal for a loser. Denial is the longest river.
Toad Croaks
European toadscompete for receptive females. A male may try to pull off another male already mounted on a female. The male in the act instantly gives a croak of objection.
The lower the croak, the tougher the toad. A higher-pitched usurper immediately knows the score and hops away. Only if the interloping toad can get down with a lower croak does further hostility ensue.
Amphibians grow their entire lives. Their sounds lower with girth. Hence, toad croak pitch is itself an honest signal, as it is entirely a matter of biophysics. A toad can’t fake his croak.
Cricket Song
Cricketsface the same situation as European toads. Females prefer large males, as they are better providers.
After the Sun goes down, male crickets rub their wings together to sing their laments for love. Larger males sound romantically forlorn at a lower tone and are more likely to find love.
Lizard Flashes and Dances
During mating season, male veiled chameleonssignal their aggressive intentions and fighting prowess by adjusting the brightness of their skin. Individuals with bright stripes are most likely to charge. Once in combat, those whose heads most quickly brighten are likely to win a bout.
Male side-blotched lizards establish territories where they consort with one or more females. When challenged, males perform aerobic displays to each other. The duration of display accurately reflects a male’s physiological state and determines the winner.
Hyrax Songs
Hyraxesare thickset rodent-like creatures, 30–70 cm long and 2–5 kg. As early English biblical translators did not know of hyraxes, they are referred to in The Bible as coneys, a term usually applied to rabbits. Hyraxes are closely related to elephants.
As a courtship ritual, male hyraxes sing to potential mates. Their songs consist of a series of various sounds: wails, snorts, and chucks. Hyrax songs are a musical curriculum vitae.
Wails indicate weight. The more wails, the heftier the singer. Chucks communicate body size (length, head diameter) and stress level. A series of snorts inform about social dominance, condition of the pelt, and quality of certain male hormones.
These fitness signals cannot be counterfeited. Thus, female hyraxes are sung a reliable précis of the strengths and weaknesses of each of their potential mates.
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It is widely accepted that a sexual ornament can reveal quality because of the challenges associated with producing or bearing such traits. ~ Innes Cuthill et al
Animals horns and other traits of male dominance reflect fitness: good genes naturally, but more particularly the quality of early development, notably nutrition. Any developmental mechanism with hormonal sensitivity is reflected in the variable traits which demonstrate fitness. Hence, biological efficiency translates into honest communication by way of developmental physiology. Some things can’t be faked. Animal virility is one of those things.
Through honest communication many animals quickly gain accurate information about the fighting ability of an opponent, make a probabilistic determination, and terminate encounters they cannot win. Likewise for sexual selection, where honest signaling conveys economy of effort in choosing a mate.
Deception
“Honesty may be the best policy, but it’s important to remember that apparently, by elimination, dishonesty is the 2nd-best policy.” ~ American comedian George Carlin
Every organism, and every facet of its functioning, evolves toward optimization. Efficiency comes from making the best use of limited resources. A wondrous aspect of biology is its high degree of coherency.
The flip side of efficiency goes beyond making the most of something: getting something for nothing. Deception is the means.
Deception is a very deep feature of life. It occurs at all levels – from gene to cell to individual to group – and it seems, by any and all means, necessary. ~ American evolutionary biologist RobertTrivers
Virusesare masters of disguise. Among other stratagems, they coat themselves in proteins of the host they hope to infect to go undetected.
Proteins stick to the viral surface, forming a protein corona. The virus remains unchanged on the genetic level. It just acquires different identities by accumulating different protein coronae on its surface depending on its environment. This makes it possible for the virus to use extracellular host factors for its benefit. ~ Swedish molecular biologist Kariem Ezzat
The most benign deception is to be left alone. Camouflage and mimicry commonly evolve to that end.
Defensive deception may extend to suggestive subterfuge. An animal approached by a killer may try to defend itself by giving its attacker a fright. Startling a predator makes it pause, at least allowing the prey a chance to escape, if the shock alone is not enough to dissuade. Some caterpillars startle their attackers by raising themselves up like small snakes.
The key to instilling horror is suddenness. Nothing gradual startles anything.
The most common spook is a sudden show of a large pair of eyes. Animals generally judge body size by the size of the eyes. The abrupt appearance of prodigious peepers provokes doubt. Some reptiles and birds sport outsized false eyes that they flash to make a potential attacker hesitate.
If shock is not an option, there is another way to make oneself unappetizing: death.
Vine weevilsunder duress tuck their legs under their barrel-shaped bodies, then roll onto their backs. These flightless, ponderous walkers have few viable alternatives to playing dead when threatened. The weevil wheeze often deters further interest from potential predators who prefer their snacks still kicking.
More manipulative are work-saving devices, where receivers get duped into acting against their own self-interests. Rubes often become dinner.
An anglerfishhas a fleshy filament protruding from the front of its head that acts as deceptive advertising. Small fish that snap at an anglerfish’s lure get eaten. A deep-sea squid with a lure at the end of a long tentacle practices the same trick.
Margays are arboreal catsnative to the Americas. They sometimes imitate the calls of various prey, such as tamarins, to lure them to dinner.
Certain species of Photurus female fireflieshave 2 ways of flashing their lights. One pattern attracts males of her species for mating. The other mimics the flash of a smaller firefly belonging to the Photinus genus. A Photinus male answering the call of a Photorus female turns the amorous male into a meal: the firefly femme fatale kills and consumes him.
Sometimes females have had enough of males and just want to be left alone. Once her eggs have been fertilized, female Mooreland hawker dragonfliesavoid further male encounters by feigning death. With good reason. Male hawker dragonflies don’t give up trying to mate, nor are they any help in protecting eggs. What’s more, they can pull sperm from prior inseminations by other males out of a female’s reproductive tract with their penises; a procedure fraught with health risk for the female.
Some ant queens are consummate percussionists. Equipped with unique, tiny, ridged organs, they stridulate royal fanfares that keep workers in line. Parasitic butterfly larvae residing in the colony precisely imitate a queen’s drumbeats – an act of musical piracy that induces worker ants to regurgitate food right into the parasites’ mouths.
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The botanicalkingdom is rife with beguilement. 5% of flowering plants entice pollinators via various ruses. Others deceptively attract insects for their own consumption.
Carrion flowers, which smell of rotten meat, attract scavenging beetles and flies, which it then slathers with pollen.
Passion vines, beloved by some butterflies as food for their caterpillars, have yellow spots on their leaves that look as if eggs had been laid by a gravid female. This puts the butterflies off from laying their own eggs, as they suppose there will be too many larvae for the plant to feed.
Numerous carnivorous plants lure insects with sweet odors, only to devour them.
Walk Like an Ant
Ants are aggressive in defending themselves: well-armed with bites, stings, and acids. Little jumping spiders – not so much. Under duress, all a tiny spider can do is flee as fast as it can, which may not be enough to avoid becoming a snack. So, some jumping spiders walk like ants: using all 8 legs, but frequently pausing to raise their forelegs and mimic ant antennae. All a potential predator sees is 6-legged trouble; not the spider it’s looking for.
Backstabbing Butterfly
The Peruvian metalmark butterfly plays the long con on its hosts. (The metalmark attribution refers to small metallic-looking spots commonly found on the wings of these mostly Neotropical butterflies.) As a caterpillar, the butterfly cooperates with ants, winning them over with sugary secretions. In return, the ants defend the caterpillar from predators.
When the caterpillar becomes a butterfly, it turns on its protectors: plundering the ants’ carefully tended nectar supply, which is harvested from bamboo shoots that pay for protection with sweets.
Ants usually fiercely defend their favored food source. The metalmark butterfly, which smells like its benevolent younger self, is an exception. The duped ants get nothing in return.
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Bird Orders
Although there are 24 avian orders, birds are commonly bifurcated into passerines and non-passerines. Passerines constitute more than half of all bird species. Sparrows, wrens, finches, and tits are passerines. The cerebral star of the passerines are corvids: savvy crows, ravens, and jays.
Passerines are sometimes referred to as perching birds, or, less accurately, songbirds, as songbirds are a passerine suborder. The name passerine derives from the scientific name for the house sparrow, Passer domesticus.
Examples of non-passerines include flamingos, fowl, doves and pigeons, birds of prey (hawks, eagles, falcons, owls), swifts and hummingbirds, water & sea birds (pelicans, storks, petrels, gulls, waterfowl, loons, penguins), woodpeckers, and parrots.
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A large minority of cuckoospractice brood parasitism: passing their own eggs off on another species to raise. While nonparasitic cuckoos lay white eggs, like most non-passerines, many parasitic cuckoos lay colored eggs that match those of their passerine hosts. Matching eggs is an ongoing challenge for brood parasites as victims adapt via egg changes and enhanced forgery detection, much like governments do to protect against counterfeit currency.
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Deception descends to the molecular level. Pathogenic microbes mimichost functions to exploit cellular machinery and evade immune defenses. For one, viruses steal genes from their host and then, like filching a key to a lock, encode host proteins that let a virus in, and then put a target cell to work for its own nefarious intent.
Pathogensare often masters of deception. In plants, a pathogen’s first ploy is to deploy virulence effectors to disable host defense. Potential victims defeat these effectors with proteins that guard effector targets. Pathogens that have caught on to this produce proteins which mimic protein guards, and instead act to effect virulence. This ruse has a victim put its guard down while being invaded.
“We are never deceived; we deceive ourselves.” ~ German politician Johann Wolfgang von Goethe
Deception is a common tactic both among conspecifics, and between species, particularly predators and prey. Interspecies’ deception communication often becomes a coevolutionary spiral: where a deceiver becomes increasingly caught out as the predator wises up, ratcheting the quality of deception to another level.
Wintergreen Oil
Wintergreen oilis an organic ester made by many plants, particularly wintergreens, as an anti-herbivore defense. Citrus tree leaves produce wintergreen oil when damaged as a warning to relatives. The jumping plant louse hones in on the scent of wintergreen oil from citrus trees, whose sap is the only food of its young offspring.
Liberibacter bacteria infect citrus trees. They hijack plant scent production, forcing the release of wintergreen oil to mimic an attack by plant lice.
The jumping plant lice that fly to the source are duped: they will not find much food there, as the bacteria have drastically lowered the nutritional quality of infected leaves.
This is a trick that forces the lice to seek another tree, this time carrying the bacteria who have hitched a ride. Thus, the bacterial infection spreads to other citrus trees, where it causes the deadly citrus greening disease.
The wasp Tamarixia radiata lays its eggs on young plant lice so that its larvae can feed on the lice. The wasp finds its prey by eavesdropping on the odor exchanged between bacteria, trees, and lice.
Hence, wintergreen oil is a scent of deceit, shared among plants, bacteria, lice, and wasps, with the plants and lice paying the price.
Camouflage
Many animals that suffer predation have adaptively adopted camouflage that allows them to hide in plain sight. To be most effective, an animal must mentally match itself to its background; a feat which seems highly unlikely, as it would require that the animal know what its body looks like, and how it fits into the landscape. Yet that is exactly what animals seeking cover do.
Animals select backgrounds or positions to improve concealment. ~ English zoologist Martin Stevens et al
How animals could possibly have this fantastic cognitive ability is a mystery.
Fish Scales
Open-ocean fish have silvery scales for skin that re-flect light from above such that the reflected intensity is similar to the background intensity, rendering a fish invisible when looking up, as a predator would; except, many fish can detect polarization – the directional vibra-tion of light waves.
If fish scales acted as simple mirrors, they would im-part a polarization signature to the reflected light much different from the more random polarization of the back-ground light field. This signature would be apparent to a predator able to discriminate polarization. But fish scales scatter polarization, making the camouflage complete. Hence, fish scales render predation a more demanding task. Camouflage via properly polarized fish scales is an amazing evolutionary feat of molecular fine-tuning.
Alternate Concealments
Animals in the lower mesopelagic zone (600–1,000 meters depth) of the oceans have converged on 2 major strategies for camouflage: transparency and red or black pigmentation. ~ American biologist Sarah Zielinski& Sönke Johnsen
Hiding in the ocean depths is not as easy as it might seem. Cephalopods illustrate the camouflage conundrum.
Some of their predators, like hatchet fish, hunt by diving deep and looking up for silhouettes of potential food. To avoid being seen, it helps to be transparent and so not cast a shadow.
Other predators, like deep-sea dragonfish, patrol using bioluminescent searchlights that reflect off clear flesh. In the presence of these glowing adversaries it’s safer to be as dark as the surrounding water.
The common clubhook squidand the Japetella octopusindependently evolved a nifty solution to this dilemma: instantly switch disguise.
To alternate camouflage, the 2 cephalopods have distributed sacs of black pigment which they can twitch-switch. When it’s dark and the cephalopods want to be transparent, the sacs form compact spheres, letting the creatures’ glassy flesh show. When a light appears, the sacs flatten and stretch toward one another, shrouding the cephalopods in pigment.
“In less than a second, it’s on and off.” ~ Sarah Zielinski
Looking Dangerous
Many mothsand butterflies have coloration patterns that act as camouflage. As insectivorous birds have caught on, adaptation has furthered the camouflage cycle.
Small birds panic at the sight of predatory birds, many of which, especially hawks and owls, possess large, prominent eyes.
Automeris coresus is a moth that lives its larval stage disguised as a spiny plant. This is only its first disguise. An adult has cryptically colored forewings which blend into the terrain when the moth is settled.
Disturb a sitting moth and it will flash open its forewings to show its hindwings, which display eyespots. An agitated moth draws in its legs and rhythmically rocks, producing a startling effect that frightens small birds.
The Brazilian owl butterfly has an even closer proximity to owl eyes, including white flecks in an arc, exceedingly like a glint of light made by reflection of an owl eye. Hungry little songbirds are too spooked to try to take a bite out of the owl butterfly.
Mocking Weevils
Animals with bright colors are often a warning of inedibility to potential predators. Sometimes, as a ruse, perfectly tasty creatures look like those who don’t make a decent meal. English entomologist Henry Walter Batescalled such deceivers “mockers.”
English naturalist Alfred Russel Wallacecontemplated evolution at the same time Charles Darwindid. The two published their musings on natural selection contemporaneously.
Among his extensive fieldwork, Wallace avidly collected insects. The beautifully colored Pachyrhynchus weevils of eastern Asia and Australia were in Wallace’s collection.
Wallace considered these beetles hazardous: not because they were poisonous, but because their body armor would be impossible for predators to chew. (Wallace found this out firsthand when he tried to pin Pachyrhynchus weevils to one of his collection boards. Unable to do so, Wallace had to resort to a drill for the chore. 150 years after Wallace proposed Pachyrhynchus as bite-proof, researchers confirmed that these weevils were not in the least toxic.) And so they are (impossible to chew). A bite of this beetle by a bird is enough to spit the bug out like it was a stone.
Only the adults are tough as nails. Young weevils are quite digestible. Their shells only toughen after 2 months. Hence, juvenile Pachyrhynchus are mockers of their future selves.
The Scent of Food
“For many animals, vision is less important than their sense of smell. Because predators often rely on odors to find their prey, even visually camouflaged animals may stick out like a sore thumb if they smell strongly of ‘food’.” ~ Australian marine biologist Rohan Brooker
Orange-spotted filefishexclusively feed on a specific coral. The coral is not just chow. Filefish absorb the coral’s chemical composition and thereby smell like their food. The chemical crypsis is good enough to fool predators on the reef which rely upon scent as well as sight to suss their prey.
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One issue of deception goes to intent. Evolution may result in coloration where the wearer puts forth no effort for the advantage. Phenotype alone may be the complete deceit. But in many instances, behaviors enhance the deceptive look.
Many deceptions involve cunning. Ground-nesting birds, such as plovers, will lure a predator away from their nest by feigning a broken wing. In doing so, they monitor a predator, such as fox, to see whether the ruse works: whether the fox is following the bird, or still heading to the nest. Foxes may learn to see through such a ruse and suspect that they are being led away from edible eggs or chicks.
Another distraction display is the “rodent run.” Shorebirds lure a predator away from their nest by running rapidly in a low crouch that appeals to the mouse-catching instincts of mammalian carnivores. Once the danger is passed, the bird sneaks back to its nest.
Some fly-catching birds hunt in groups of mixed species, giving alarm calls at the approach of a bird-eating hawk. Flycatchersfeed on insects flushed out by the flock. A flycatcher will sometimes intentionally raise a false alarm to distract other birds, thereby enhancing its own chance of finding fare.
Drongos
Drongos are exceedingly deceptive; their vocabularies are immense; and they match their deception to both the target animal and its past response. This level of sophistication is incredible. ~ American ornithologist John Marzluff
Fork-tailed drongosare glossy, black African songbirds with ruby-colored eyes. They mimic the alarm calls of other species to scare an animal away. Then they swipe the dinner of the duped. Drongos get about a quarter of their food from deceptive theft.
Those deceived do catch on. When a false alarm stops working, a drongo switches to another species’ warning cry, which usually works for a while.
Drongos have as many as 51 different alarm calls in their repertoire. 6 of those drongos use to warn of various predators. The other 45 are the alarms of others.
Drongos keep an eye out for raptors and other predators. When spotted, a drongo utters a shrill metallic alarm.
Nearby birds and meerkats pay attention to drongos: dashing for cover with an alarm, just as they would when one of their own calls out a warning.
Having drongos around is somewhat helpful, as they are sharp-eyed. Animals nearby do not have to be as vigilant and can devote more time foraging.
That is exactly what drongos want – productive foragers. Drongos have an “all-clear” call to encourage business-as-usual, which means more for them to steal.
The benefit of having lying thieves around is decidedly mixed. If a drongo spots a meerkat with a tasty fat grub, it emits a treat-dropping false alarm.
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Cuttlefishhave the splendid ability to change their patterned colorings quickly at will. A male cuttlefish may flash an elaborate courtship display to a female on the side of his body that she can see while presenting a deceptive business-as-usual pattern on the other side, so that another male looking on has no reason to perceive the suitor as a rival.
Topisare antelopes that live on the savannas of equatorial Africa. A male topi might keep a potential mate from wandering away by deceptively snorting in alarm that there is a lion nearby. This trick has limited effectiveness. If plied too many times, the female catches on and walks away.
Elephantscan be deceptive. A zoo elephant finished off its hay ration, then nonchalantly idled over to its neighbor’s hay pile, aimlessly swinging its trunk and nabbing bites on the sly.
Dogs are deceiving. They are also quick to catch on when being deceived.
Primate Deception
Monkeysare gregarious, with varying degrees of rigidity in their social hierarchies. Spider monkeys live in large mixed-sex groups of up to 500 members. Their social hierarchy is relaxed. Capuchins live in troops 90% smaller than spider monkeys, with a more decided social hierarchy, but not nearly as stern as that of macaques.
Macaques have a strict social hierarchy. If a lower-level macaque has eaten berries and left none for a more dominant one, the ranking macaque is entitled to remove the berries from the subordinate’s mouth. So, subordinates are careful to conceal their consumption, or their knowledge of food source, if a higher-ranking macaque is about.
Captive monkeys – capuchins, spiders, and macaques – were shown how to unlock a box to get a food reward. The trained monkeys were low-ranking in social standing. When a more socially dominant monkey was around, a trained monkey, especially a macaque, would forgo the treat: ignoring the box and not revealing how to open it.
Simians are deceivers. A subdominant baboon, on being attacked by a senior, may feign fright from a pretend predator approaching – a distraction designed to allow the younger baboon to slip away without further abuse.
Chimps will call others when they find food in abundance. Conversely, when a small amount is discovered, they remain silent or even decoy others to a wrong location.
“You only lie when you’re afraid.” ~ American mobster John Gotti
