Aye-aye

Encounters are recorded at night in the coastal rainforest of eastern
Madagascar, on the Masoala peninsula and inland along the same wet ridge.
The animal is a primate roughly the size of a house cat, with coarse black
fur, a tail longer than its body, ears out of all proportion to the skull,
and incisors that grow continuously and are worn back by use. One hand
detail is consistent across every account: the middle finger is far thinner
and longer than the others, and is carried curled and held clear of the bark.

The finger is the whole file. The animal taps along a branch, listens to the
returning sound with those ears, opens the wood with the incisors and takes
what is inside with that one finger. No other primate is known to feed this
way. In several districts it is killed on sight, not for meat but for
what a visit is held to mean, and that practice — not
habitat loss alone — is why the species was written off as extinct in 1933.

Sealed. It was found again in 1957, on an offshore island, and has been kept
under continuous record since. Retained here for a specific reason: this is
a file that was closed once in error, by people who had good evidence and
read it the wrong way round.