There's a little extra thumb-thing on the hand of the aye-aye, a strange-looking nocturnal lemur native to Madagascar.
David Haring/Duke Lemur Center, Tiny Fox Lab

The aye-aye, a strange-looking nocturnal lemur native to Madagascar, has a small extra pseudothumb by its wrist. They are the only primate to have evolved an extra finger to help with grasping. – Tiny Fox Lab Facts

Preview photo credit: David Haring/Duke Lemur Center
Source: livescience.com/aye-aye…