The aye-aye is a long-fingered lemur, a strepsirrhine primate native to Madagascar with rodent-like teeth that perpetually grow and a special thin middle finger that they can use to catch grubs and larvae out of tree trunks.
Closeup of the hand showing the elongated digits and the thinner third digit
An aye-aye foraging, c. 1863, Joseph Wolf
Lemurs are wet-nosed primates of the superfamily Lemuroidea, divided into 8 families and consisting of 15 genera and around 100 existing species. They are endemic to the island of Madagascar. Most existing lemurs are small, have a pointed snout, large eyes, and a long tail. They chiefly live in trees and are active at night.
A life restoration of Babakotia radofilai, a sloth lemur that became extinct less than two thousand years ago
Close-up of a ruffed lemur's foot, showing the toilet-claw on the second toe and nails on all other toes
A six-tooth version of the strepsirrhine toothcomb in a ring-tailed lemur, with canine-like premolars behind it