This unique nocturnal primate is native to the island of Madagascar and is the only primate in the world to have a special middle finger that is used to tap on tree trunks to locate food. The Aye-Aye is a medium-
From Wikipedia
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.