The Web of Life – Primates

Primates

PrimateĀ is an order bifurcated into prosimians and simians (aka anthropoids). Prosimians include lemurs, bushbabies, and tarsiers, among others.

Simians include monkeys, apes, and humans. Among simians, only monkeys have tails. 264 monkey species are known.

One salient characteristic shared by all primates is a prolonged childhood. Though particulars vary as to caretakers beyond mothering, all primates practice extensive parental care.

The intellectual benefit of parenting is education, termed social learning. All young primates learn a variety of skills from their elders, with mom as primary teacher.

Lemurs

Floating on a raft of vegetation, the common ancestor of lemursĀ arrived on the shores of Madagascar from Africa ~65 MYA. They adapted and diversified to 100 species. Some lemurs were as large as gorillas until men came and killed them off.

Lemurs are strepsirrhine primates: a suborder that also includes African bushbabies and pottos, along with lorises endemic to India and Southeast Asia. Strepsirrhines are defined by their wet nose. All are primarily arboreal.

Lemur males and females are similarly sized and look much the same. It can be hard to tell a male from a female.

All lemurs have toothcombs: teeth perfectly shaped for grooming, which is an important part of lemur social life.

Lemurs are gregarious and generally docile, living in close-knit groups of usually less than 15 individuals. Lemur groups share food and nests, though scarcity can make them stingy and self-serving.

As with all social organisms, individuals have their own preferences for sociability. Some lemurs are especially extroverted, others reserved, though all have close social relations with others.

Lemurs have a variety of ways to express themselves: with postures and gestures, tactility, smells, and vocalizations. (Lemurs lack many of the muscles commonly used for primate facial expressions, limiting this avenue of communication.) Groups develop their own lingo over time.

Despite their general peaceability, lemurs do sometimes have arguments in their family, and with other families. Such is social life.

Lemurs have an especially keen sense of smell. They recognize one another by scent.

Lemurs sometimes mix their scented bodily secretions to create aromatic confections, which are used for various purposes, including marking territory and in dominance contests: a ritual known as “stink-fighting.” Ring-tails lemurs have distinct scent glands on their wrists and chests which provide honest signals of a lemur’s health condition.

Lemurs avoid inbreeding by smell. To divert incest, gray mouse lemur females recognize the signature of paternal relation in male mating calls.

Sifakas are a genus of nocturnal lemur. To signify their bond, mated pairs of sifaka come to smell alike. Couples with offspring smell the same, owing to the frequent exchange of body fluids that comes with mating, grooming, and other physical contact.

In some lemurs, such as ringtails, females stay with their natal group, whereas males migrate to other groups once mature. Other lemurs have different habits in this regard.

Females dominate the social order, including over males. You can tell a great deal about a group’s social rankings based on the order in which grooming is done. Groups of males are common, as they are with other primates. Nocturnal lemurs forage alone at night, but often nest together during the day while they sleep.

The selfsame body sizes and social dynamics among lemurs figure into their sexual practices. In finishing mating, a male deposits a liquid-protein plug inside the female’s reproductive tract. The plug hardens and stays in place for a day or 2. Since females are sexually receptive for only 1 day each year, the plug ends her mating for the year. As males don’t dominate but can assure their paternity in wooing a female, there is no need for competition between males.

Lemurs eat more leaves than fruit because the fruit in Madagascar is especially low in nitrogen.

When foraging alone, lemurs keep an ear out for the alarm calls of others, including different lemur species, and even various birds. They understand the varied languages, such as bird calls, that specify a threat from above, or an “all clear” call.

Females of nocturnal lemurs tend to share a nest with other females, along with offspring and possibly one male. Diurnal lemur sociality is much like monkeys and apes in behaviors and variety.

Lemurs learn from their life experiences, and from those around them (social learning). More mature females make better mothers.

Though arboreal, 2 species of dwarf lemur that live in high-altitude rain forests dig underground burrows in which to hibernate during the cold months. They store fat in their tails. Another dwarf lemur hibernates in the hollows of tree trunks. These are the only primates known to hibernate.