The Elements of Evolution (44-11) Camouflage


As a protective stratagem camouflage independently evolved in various sea urchins, gastropods, crabs, insects, amphibians, cephalopods, reptiles, birds, and mammals.

Japanese quail understand the value of camouflage. Hens know the patterning of their eggs and carefully lay them in locations that hide them best.

Camouflage has a variety of forms. The best known is coloration, which may change seasonally and/or at separate stages of life, if not at will, as with coleoids (squid, cuttlefish, and octopuses). Some cuttlefish and octopi can create exquisitely detailed and exact colored patterns via their minds in milliseconds despite being color-blind.

Clupeids are a family of ray-finned fishes that includes herrings, sardines, and shades. Silvery clupeids convergently evolved a multilayer skin made of 2 types of guanine crystals, each with distinct optical properties. The different crystals are meticulously arranged to cancel the polarization of light reflected off the fish.

These fish evolved this particular multilayer structure to help conceal them from predators, such as dolphin and tuna. They found a way to maximize their reflectivity over all angles they are viewed from. This helps the fish best match the light environment of the open ocean, making them less likely to be seen. ~ English physicist Nicholas Roberts

Concealment camouflage is often coupled with behaviors to secure the effect, such as prey staying stock still, or predators slowly stalking.

With mimesis a creature’s camouflage makes it look inconsequential. Posturing as a plant is a common ploy. Both prey and predator make such a masquerade. To avoid being munched, a grasshopper looks like a leaf. A stick insect passes for a twig. As a predatory ploy, a flower mantis climbs to the top of a suitable plant and appears to be in bloom, awaiting prey.

The orchid mantis specializes in pink orchids. A mantis sways side-to-side, as in the breeze. Various small flies land on and about it, attracted by a black spot at the tip of its abdomen that resembles a fly; exactly what the mantis is hoping to nab.

There are numerous cryptic behaviors employed situationally. Most mimic the environment. Leafy sea dragons sway like the seaweed among which they rest.

As stealth hunters, dragonflies employ motion camouflage: flying in way that hides them from their prey.