- Primate species are gibbons, langurs, lorises and macaques.
- Only in recent decades have prosimians - a suborder of primates that includes lemurs, lorises, bushbabies, and tarsiers - begun to be studied systematically.
- However, some primates such as apes, spider monkeys, and lorises have morphological and behavioral specializations that may enhance efficiency during vertical climbing.
- Aye-ayes have large, naked, mobile ears, a muzzle that is shorter than that of most lemurs but longer than lorises, and large eyes with yellowish brown irises.
- Fossils suggest that lemurs, bush babies, lorises, aye-ayes, and their relatives (the prosimians) spilt off from the ancestors of monkeys and apes around 55 million years ago.