Aye-aye

The aye-aye (Daubentonia madagascariensis) is a long-fingered lemur, a strepsirrhine primate native to Madagascar with rodent-like teeth that perpetually grow^[3] and a special thin middle finger that they can use to catch grubs and larvae out of tree trunks.

It is the world's largest nocturnal primate.^[4] It is characterized by its unusual method of finding food: it taps on trees to find grubs, then gnaws holes in the wood using its forward-slanting incisors to create a small hole into which it inserts its narrow middle finger to pull the grubs out. This foraging method is called percussive foraging, and takes up 5–41% of foraging time.^[5][6] The only other living mammal species known to find food in this way are the striped possum and trioks (genus Dactylopsila) of northern Australia and New Guinea, which are marsupials.^[7] From an ecological point of view, the aye-aye fills the niche of a woodpecker, as it is capable of penetrating wood to extract the invertebrates within.^[8][9]

The aye-aye is the only extant member of the genus Daubentonia and family Daubentoniidae. It is currently classified as Endangered by the IUCN. A second species, Daubentonia robusta, appears to have become extinct at some point within the last 1000 years, and is known from subfossil finds.^[10]