aye-aye

The aye-aye (Daubentonia madagascariensis) is a lemur, a strepsirrhine primate native to Madagascar that combinesrodent-like teeth that perpetually grow and a special thin middle finger.


It is the world's largest nocturnal[4] primate, and is characterized by its unusual method of finding food; it taps on trees to findgrubs, then gnaws holes in the wood using its forward slanting incisors to create a small hole in which it inserts its narrow middle finger to pull the grubs out. This foraging method is called percussive foraging which takes up 5-41% of foraging time. The only other animal species known to find food in this way is the striped possum.[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.


The aye-aye is the only extant member of the genus Daubentonia and family Daubentoniidae. It is currently classified asEndangered by the IUCN; and a second species, Daubentonia robusta, appears to have become extinct at some point within the last 1000 years.












Anatomy and morphology


Young aye-ayes typically are silver colored on their front and have a stripe down their back. However, as the aye-ayes begin to reach maturity, their bodies will be completely covered in thick fur and are typically not one solid color. On the head and back, the ends of the hair are typically tipped with white while the rest of the body will ordinarily be a yellow and/or brown color.


In length, a full-grown aye-aye is typically about three feet long with a tail as long as its body. Among the aye-aye's signature traits are its fingers. The third finger, which is thinner than the others, is used for tapping and grooming, while the fourth finger, the longest, is used for pulling bugs out of trees.[14] The middle finger is unique in that it possesses a ball-and-socket metacarpophalangeal joint.[18]


The complex geometry of ridges on the inner surface of aye-aye ears helps to sharply focus not only echolocation signals from the tapping of its finger, but also to passively listen for any other sound produced by the prey. These ridges can be regarded as the acoustic equivalent of a Fresnel lens, and may be seen in a large variety of unrelated animals, such aslesser galago, bat-eared fox, mouse lemur, and others.


Females have two nipples located in the region of the groin.