The Aye-aye (Daubentonia madagascariensis) is a lemur, a strepsirrhine primate native to Madagascar that combines rodent-like teeth with a long, thin middle finger to fill the same ecological niche as a woodpecker. It 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 elongated 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.
The Aye-aye is the only extant member of the genus Daubentonia and family Daubentoniidae (although it is currently classified as Near Threatened by the IUCN); a second species, Daubentonia robusta, appears to have become extinct at some point within the last 1000 years.
Aye-aye
Habitat
The Aye-aye lives primarily on the east coast of Madagascar. Its natural habitat is rainforest or deciduous forest, but many live in cultivated areas due to deforesting. Rainforest Aye-ayes, the most common, dwell in canopy areas, and are usually sighted upwards of 700 meters altitude. The Aye-aye sleeps during the day in nests built in the forks of trees.
Behavior
Social interaction
The Aye-aye is classically considered ‘solitary’, but recent research suggests that they are more social than once thought. It usually sticks to foraging in its own personal home range, or territory. The home ranges of males often overlap and the males can be very social with each other. Female home ranges never overlap, though a male’s home range often overlaps that of several females. The male Aye-Aye live in large areas that are up to 80 acres (320,000 m2) while female have smaller living space that goes up to 20 acres (81,000 m2). Regular scent marking with their cheeks, neck and genitals is a way that aye-ayes let others know of their presence and repel intruders from their territory.[13] Like many other prosimians, the female Aye-aye is dominant to the male. The Aye-aye is not monogamous by any means, and often competes with each other for mates. Males are very aggressive in this regard, and sometimes even pull other males off a female during mating. Outside of mating, males and females interact only occasionally, usually while foraging.
After impregnating a female, the male usually stays in close proximity until the infant is born and has matured a bit. The father will sometimes share food with the infant, but otherwise infants’ primary source of social interaction is with their mothers. Mothers and infants often wrestle, chase, and play “peek-a-boo” for entertainment. After 13 weeks, infants are usually ready to interact with other young Aye-ayes, usually by play-fighting.
Foraging
The Aye-aye begins foraging anywhere between 30 minutes before or 3 hours after sunset. Up to 80% of the night is spent foraging in the canopy, separated by occasional rest periods. The monkey-like body of the Aye-aye enables it to move vertically with ease. It climbs trees by making successive vertical leaps, much like a squirrel. Horizontal movement is more difficult, but the Aye-aye rarely descends to jump to another tree, and can often cross up to 4 km (2.5 mi) a night.
Infants are fully dextrous within a month of birth. At first they can only climb on a branch hanging upside down, but they gradually work their way up to the various acrobatic feats that adults can perform. Curiously, walking and running on the ground is often hardest for an Aye-aye to master.
Diet
The Aye-aye commonly eats nuts, and also grubs, fruits, nectar, seeds, and fungi, classifying it as an omnivore. It often picks fruit off trees as it moves through the canopy, often barely stopping to do so. An Aye-aye not lucky enough to live in its natural habitat will often steal coconuts, mangoes, sugar cane, lychees and eggs from villages and plantations. Aye-ayes tap on the trunks and branches of the trees they visit up to 8 times per second and listen to the echo produced to find hollow chambers inside. Once a chamber is found they chew a hole into the wood and get grubs out of that hole with their elongated and bony middle fingers.
Social foraging
Though foraging is mostly solitary, it will occasionally forage in groups. Individual movements within the group are coordinated using both sound (vocalisations) and scent signals.
History
The original meaning of the name Aye-aye has been lost, as the originating language is extinct. There is a hypothesis that the word “aye aye” signifies simply a cry of alarm to alert others to the presence of this animal, which many Malagasy consider an ill omen.
With D. robusta’s extermination, the D. madagascariensis Aye-aye was thought to be extinct. However, it was later rediscovered in 1961. Six individuals were transported to Nosy Mangabe, an island near Maroantsetra in eastern Madagascar. Recent research shows that the Aye-aye is more widespread than was previously thought, but is still near threatened.
There are several Aye-ayes kept in zoos. The largest collection of Aye-ayes and the most successful breeding program with a current population of 22 individuals is at the Duke Lemur Center at Duke University, Durham, North Carolina, US. Several also reside outside of the US at various locations.
