Aye-aye

Aye-aye
Photo by Tom Junek.
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Suborder: Strepsirrhini Infraorder: Chiromyiformes Anthony and Coupin, 1931 Family: Daubentoniidae Gray, 1863 Genus: Daubentonia É. Geoffroy, 1795 Species: D. madagascariensis
Binomial name
Daubentonia madagascariensis (Gmelin, 1788)

The Aye-aye is the sole living member of the family Daubentoniidae. Aye-ayes are a type of lemur and are quadrupedal leapers and clingers. They are found only in Madagascar and are the largest nocturnal primate in the world. Like many primates today, their survival is threatened by loss of habitat and human predation.

Physical Characteristics

The physical appearance of Aye-ayes is extremely unique. They are about the size of a cat and weigh 2.4-2.8kg (5-6lbs). Aye-ayes do not exhibit sexual dimorphism. They have large ears and long, bushy tails. Their coat is grey-black with white tips and their digits are elongated, especially the middle fingers. According to Jeffrey Cohn's article "Madagascar's mysterious aye-ayes," "experimental psychologist Garrett Milliken...learned that aye-ayes can move their third finger independent of the others. Milliken also found they can extend the fingertip 30 degrees backward and 90 degrees to each side."

Aye-ayes have a reflective tapetum that helps them detect light at night and makes their eyes shine like a cat's do when you shine a flashlight at them.

The front teeth of Aye-ayes grow continuously like a rodent's -- a unique trait among primates. These large, powerful incisors help them tear through wood to get to the grubs they like to eat so much. They also use their teeth to eat the tough fruits they like, such as coconuts.

Their appearance is so strange that the people of Madagascar are afraid of them and consider them to be a bad omen.

Habitat

Aye-ayes live in forests in Madagascar, mainly on the Eastern coast. They spend most of their time in trees, and build nests to sleep in during the day.

Diet

Aye-ayes take over the ecological niche that woodpeckers usually occupy in other areas of the world. They use echolocation to find their food. First, they use their especially long middle fingers to forage for food by tapping them on things like wood. They then use their large ears to listen to the sound the wood makes in order to find hollow spots where larvae live. They will then use their long incisors to tear a hole in the wood and fish out the larvae with their middle finger. Aye-ayes eat mainly larvae, nuts, and fibrous fruits such as coconuts and mangoes. They therefore are categorized as omnivores.

Aye-ayes will sometimes raid plantations for food. Because of this fact, farmers often do not like them and will kill them.

Behavior

Aye-ayes are mainly solitary creatures. They spend roughly 80% of their time alone and rarely sleep with other aye-ayes, although according to an article entitled "Nocturnal Researchers tune their ears to our ancestors" by Elizabeth Culotta, "different individuals occupy the same nest on subsequent nights."

Tracking Aye-ayes in the wild requires following them through the forest during the night when they're active. As can be guessed, this is a difficult task even with the help of radio collars, flashlights and Malagasy guides. Because it is so difficult to study the Aye-aye, some portions of its life are still not well-known. For example, lifespan in the wild is not well known, but in captivity they usually live to be about 23 years old. Male ranges are larger than those of females and regularly overlap female ranges.

As they travel, Aye-ayes will leave marks using either their scent glands or urine to communicate with others of their species.

Reproduction

Sexual maturity for Aye-ayes occurs at about 2-3 years of age. When they're in estrus female Aye-ayes will call repeatedly to get the attention of males. Visual cues such as genital color change and swelling also alert males to the female's estrus. Aye-ayes are polyandrous, meaning that the females mate with several males. They usually only have one infant and gestation ranges from 160-170 days or about 5-6 months. Infants are weaned after 7 months and leave their mothers after two years. While hunting during the night, female Aye-ayes leave their infants "parked" in the nest.

Conservation

Aye-ayes were once thought to be the most endangered species of lemur, but have been spotted in more areas of Madagascar than most other types of lemurs in recent years. Even so, in an effort to ensure that adequate numbers of Aye-ayes exist, captive breeding programs have been created in four countries .

References

Allan, Tony & Mark Salad, ed. The Encyclopedia of Mammals. Andromeda Oxford Limited, (c) 2001.

Cohn, Jeffrey P. "Madagascar's mysterious aye-ayes". Bioscience 43 (10). (c) November 1993.

Culotta, Elizabeth. "Nocturnal researchers tune their ears to our ancestors." SCIENCE 261 (5117). (c) July 1993.

Corliss Pearl, Mary. The Illustrated Encyclopedia of Wildlife. "Prosimians: Lemurs, Bush Babies, Tarsiers, etc." Grey Castle Press (c) 1991.

Gron KJ. 2007 July 27. Primate Factsheets: Aye-aye (Daubentonia madagascariensis) Behavior. [1]. Accessed 2008 March 21.

Kite, Lorien. Nature's Children: Lemurs. Grolier Educational (c) 1999.

Massicot, Paul. Animal Info - Aye-aye. [2]. Animal Info (c) 1999-2000