The Aye-aye (Daubentonia madagascariensis) is a lemur, a strepsirrhine primate native to Madagascar that combines rodent-like teeth a special thin middle finger to fill the same ecological niche as a woodpecker. The Aye-aye is the world’s largest nocturnal primate, and is characterized by its unusual method of finding food; it taps on trees to find grubs, then gnaws holes in the wood and inserts its narrow middle finger to pull the grubs out. The only other animal species known to find food in this way is the Striped Possum. 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.
Its binomial name honours the French naturalist Louis-Jean-Marie Daubenton and the island on which it is found, Madagascar. Among some Malagasy, the Aye-aye is imitatively called “Hay-hay” for a vocalization it is claimed to make. It is supposedly from the European acceptance of this name that its common name was derived. However, the Aye-aye makes no such vocalization. The name was also hypothesized to be of European origin, with a European observer overhearing an exclamation of fear and surprise (“aiee!-aiee!”) by Malagasy who encountered it. However, the name exists in remote villages, so it is unlikely to be of European origins. Another hypothesis is that it derives from “heh heh,” which is Malagasy for, “I don’t know.” If correct, then the name “Aye-aye” might have originated from Malagasy people saying “heh heh” to Europeans in order to avoid saying the name of a feared, magical animal.