Prosimians are more primiative than their cousins the monkeys and apes. Prosimans have a black snout and a well-developed sense of smell (for a primate). They have large eyes and special adaptations of the retina that enhance their night vision. Most species are tree-dwelling animals and the anatomy of their hands and feet reflect this. Although they are good at grasping branches, they lack the highly developed dexterety of monkeys and apes.
Prosimans have a long tail that serves as a counter balance when moving and jumping. Prosimians are quadrapedal and are agile when in the trees, capable of running and leaping amongst the branches.
Prosimians produce a variety of calls. Lemurs, for example, use calls to signal threats and to communicate between members of their group. Indri maintain territories with loud wailing calls and sifakas declare their territories using "shi-fak" calls.
The various groups of prosimians have specific ranges: lemurs are endemic to Madagascar, lorises inhabit Asia, galagos and pottos live in Africa. Most prosimians inhabit forests and deforestation has had a devastating effect on many prosimian species.
About three-quarters of all prosimians are nocturla. Their retina contains a shiny reflective layer known as a tapetum which enhances their night vision. Noctural prosimians also have sensitive hearing.
Unlike other primates, prosimians reproduce during a distinct breeding season (other primates breed based on an individual cycle).
Most prosimians have a dental comb, a cluster of incisors and canine teeth that they use for grooming. They also have a toilet claw, a claw on the second toe that is used for grooming. Lemurs (which include the aye-aye, sifakas, and the indri) have a long body and large ears. They also have long limbs, and a long busy tail. Lemurs are medium to large-sized primates and are highly social, forming groups of as many as 30 individuals.
Lorises, pottos and galagos have dense, wooly fur and are smaller than lemurs. they have large eyes that face foward. They have smallears and opposable thumbs. They have short tails and in some species, there is no tail at all. Unlike many prosimians, lorises are diurnal (active during the day). Lorises feed on insects, fruit, sap and even birds' eggs. Galagos (also known as bush babies or ngapies) are small and nocturnal. They have good night vision and good hearing. Galagos are well suited for jumping and are know to jump up to 2 meters vertically. The potto (also know as Bosman's potto) is the only species in its group. They are small primates that weigh less than 1.5 kilograms. They have dense wooly fur and inhabit the rainforests of tropical Africa.
The Lorisiformes are a group of prosimians native to Africa and Asia. Members of this group include the galagos and the lorises.
The Lemuridae are a group of prosimians native to Madagascar. They include the ring-tailed lemurs, ruffed lemurs, true lemurs, aye-aye and bamboo lemurs. Lemur classification is controversial. There are estimated to be about 100 species of living lemurs divided into 15 groups, although some experts believe there are fewer species (closer to 50).