The Aye Aye of Madagascar has a very exceptional finger

American researchers have just made some amazing discoveries on the third finger of the aye aye of Madagascar, a small lemur living exclusively in Malagasy forests. According to the researchers report, the animal is able to “activate” and “deactivate” this finger, just like in computer’s control panels, according to the tasks which it is intended to perform.

According to a study released by Simons and Meyers in 2001, the finger tips of the aye aye are all covered with claws except the thumb. The thumb of the aye aye, like that of other primates, is up against the rest of the fingers. The third finger of the animal is very thin and very long. The aye aye uses it to extract larvae of which it feeds itself. The morphology of this finger is unique in that its width is inferior to that of the other fingers. This hypersensitive finger is particularly useful to the animal which uses it for a multitude of tasks in addition to that mentioned above. In fact, the aye aye uses it to groom, to extract the pulp of the coconut as well as to carry water and nectar from flowers in his mouth.

It is precisely this finger which attracted the interest of a team of researchers from Dartmouth College in the United States. With their thermal imaging cameras, they made ​​shots of the aye aye overnight. Indeed, this lemur is exclusively a nocturnal animal. He sleeps throughout the day in its nest hanging on treetops. The analysis of the color of the photos taken with these cameras allowed the researchers to follow the evolution of the animal’s body color.

Scientists have found that the third finger remains cold when not in use. The finger was like in “standby” (off) when the animal does not use it. They also found that this finger is warming very quickly when the animal uses it for finding its food. Its temperature could rise by 6°C in just a few seconds. The scientists concluded that the cooling of the finger, when it is inactive, could be explained by the very high volume-surface ratio of the finger. This ratio is inadequate to retain heat in this particular finger.