Lemurs

Lemurs are primitive primates, or prosimians, found only on the island of Madagascar and nearby small islands off the eastern coast of Africa. Although lemurs, lorises, and tarsiers are all prosimians, or "premonkeys," only the lemurs and lorises have the typical prosimian snout that, like a dog's, remains moist. This wet snout, called a rhinarium, suggests that scent is a particularly important sense to lemurs. Most lemurs, like other prosimians, also possess two built-in tools for grooming. The so-called "toilet claw" is located on the second toe of the hind foot (all other digits have a nail), and is used for picking through fur and eating. They also have a group of lower teeth (incisors) that combine into a horizontal tool called a dental comb, also used for grooming. All lemurs are nocturnal in habit.

Lemurs are classified in four families: the typical lemurs (Lemuridae); the dwarf and mouse lemurs (Cheirogaleidae); the indrids (Indriidae, including the indri, sifaka, and avahi); and the aye-aye, the lone member of Daubentoniidae.

The common name lemur means "ghost." It was given to these elusive creatures by the famous eighteenth century Swedish biologist, Carolus Linnaeus. Attracted by their large, bright eyes and strange calls, he thought they resembled the wandering spirits of the dead, called lemures in Latin (the language of science of the time). Linnaeus gave the name to many prosimians, but today the term lemur is used only for the prosimians of Madagascar and the Comoro Islands.

The lemurs of Madagascar were cut off from the mainstream of primate evolution at least 50 million years ago. In Madagascar, they evolved to occupy many ecological niches that, on the continent of Africa, were occupied by monkeys or apes. About 40 different species of lemurs evolved. Some, about as large as the great apes, are known only by their fossils.

Lemurs have flat nails instead of claws on both hands and feet. Most have 36 teeth, though the indrids have 30 and the ring-tailed lemur has 32. Many lemurs exhibit profound differences in weight and activity from one season to the next. For example, the male's scrotum, Two ring-tailed lemurs grooming eachother. Photograph by Tom McHugh. The National Audubon Society Collection/Photo Researchers, Inc. Reproduced by permission.

which holds the testicles, may enlarge as much as eight times as the mating season of summer approaches.