Читать книгу Anthropology For Dummies - Cameron M. Smith - Страница 77

One of the major divisions in the Primate order is that between the Anthropoidea (the people-like apes and monkeys) and the Prosimii (or prosimians, which are pretty different from people even though they’re clearly primates). Baboons, chimpanzees, and gorillas — all in the Anthropoidea — are very obviously similar to humans, but connecting to, say, the ring-tailed lemur (a cat-like prosimian of Madagascar that has a long, striped tail) or the tiny, bug-eyed, shrew-like tarsier that can fit in the palm of your hand is a little more difficult. Still, these animals are primates — even though they can look like a cross between a squirrel and a cat — and they typically have the following distinctive traits:

 Relatively long snouts in some species (long for primates, anyway), although they may also have very large eyes

 A dental formula of 2.1.3.3

 Small body size compared to other primates; they range from mouse-size to cat-size, averaging about 5 kilograms or 10 pounds

 Some are nocturnal and have a diet that favors insects but includes tree saps, grubs, fruit, flowers, and leaves

Nocturnal animals are most active at night, whereas diurnal species are most active in daylight. Making a living in darkness or light has effects on what foods animals eat, how they avoid predators, how they move about their environment, and so on.

Probably the strangest primate is the aye-aye of Madagascar. About the size of a cat with enormous, hairless ears, the aye-aye climbs through trees by moonlight listening for larvae beneath tree bark. When it hears a squirming treat, it uses a thin, elongated finger to scoop the meal out of the bark. Even the driest textbooks of primatology can’t help but marvel over this creature, which one author called the most “improbable” primate; another said that the aye-aye, though clearly a primate, displayed the most extreme specialization of anatomy in the order. This means that although most primates are somewhat general in their diet (many have a varied, omnivorous diet), the aye-aye is quite specialized and inflexible in its diet. Unfortunately, such specialization can prove disastrous if the prey species itself becomes extinct or somehow declines.

So if the prosimians are so strange, why are they considered primates? Well, they generally have nails rather than claws, focus on vision rather than smell for their sensory specialty, have relatively mobile wrists and ankles, and live mostly in the trees. For all these reasons (as well as connections shown to the rest of the primates in the genetic data), the prosimians are, in fact, relations (albeit some pretty strange ones; of course, they could say the same about us). Because the prosimians are very much like the earliest primates, understanding them and what they can reveal about primate origins is important; unfortunately, they’re endangered.

Many of the prosimians live on the island of Madagascar, off East Africa, where they’ve been isolated, in an evolutionary sense, for millions of years. Today almost 50 known species exist (two new species were discovered as recently as 2005), and, unfortunately, they’re all in danger of extinction. Humans first came to Madagascar just 1,500 years ago, and since that time many prosimian species have become extinct due to deforestation. You can keep up with these issues at www.wildmadagascar.org.