Aye-aye

The Aye-aye (Daubentonia madagascariensis) is a primate native to Madagascar that combines rodent-like teeth with a long, thin middle finger to fill the same ecological niche of a woodpecker. It is the world's largest nocturnal primate, and is characterized by its unique 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.

Daubentonia is the only genus in the family Daubentoniidae and infraorder Chiromyiformes. The Aye-aye is the only extant member of the genus; a second species (Daubentonia robusta) was exterminated over the last few centuries.

Physical Characteristics

The Aye-aye is the world's largest nocturnal primate, and dwells predominantly in forest canopies. It weighs about 2.5 kilograms, with the female weighing in slightly less (by an average of 100 grams) than males. Other than weight and sex organs, aye-ayes exhibit no sexual dimorphism of any kind. They all grow to 30-37 cm from head to body, with a 44-53 cm tail.

Adult Aye-ayes have black or dark brown fur covered by white guard hairs at the neck. The tail is bushy and shaped like a squirrel's. The Aye-aye's face is also rodent-like; it has the shape of a raccoon's, which house bright, beady, luminous eyes. Its incisors are very large, and grow continuously throughout its lifespan. These features contrast its monkey-like body, and are the likely cause of why scientists originally deemed it to be a rodent.

The Aye-aye's hands are arguably its most unique feature. Much like other primates, it possesses opposable thumbs, but both the hallux and the fingers are long and thin, and appear to be in a curved position somewhat similar to that of a fairy-tale witch when the muscles are relaxed. The middle finger can be up to three times longer than the others.

Gestation for the Aye-aye lasts from 5 to 5 1/3 months. Births can occur at any time during the year, and females often wait 2-3 years between births. The infant takes about 7 months to be weaned, and stays with its mother for two years. The Aye-aye matures quickly; males rarely take more than 1 1/2 years to mature, and females take about an extra year. Lifespan is not known, but the world record is 23 years in captivity.

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 primarily solitary. It usually sticks to foraging in its own personal home range, or territory. The home ranges of males often overlap, however, which sometimes leads to antagonistic conflicts. Female home ranges never overlap, though a male's home range often overlaps that of several females, thus placing him in a dominant position. The Aye-aye is not monogomous 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 sex. 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 kilometers 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, and eggs from villages and plantations.

Social foraging

Though foraging is, like most aspects of Aye-aye life, solitary, it will occasionally forage in groups. Individual movements within the group are coordinated with a set of audible and olfactory communication techniques.

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 is 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 Maroansetra in eastern Madagascar. Recent research shows that the Aye-aye is more widespread than was previously thought, but is still endangered.

There are several Aye-ayes kept in zoos, however. Several have been known to be born and reared in captivity. One, Kintana, resides in Bristol Zoo Gardens in the UK and others are found at zoos in London and Jersey (UK), at the Ueno zoo in Japan and the Duke University primate center in North Carolina. The Aye-aye was once thought to be a type of squirrel that lived underground, using its long finger to capture insects and worms.

Superstition and public controversy

The Aye-aye is not only an endangered species because its habitat is being destroyed, but also due to native superstition. Besides being a general nuisance in villages, ancient Malagasy legend said that the Aye-aye was a symbol of death. It is viewed as a good omen in some areas, however, but these areas are a minority.

Researchers in Madagascar report remarkable fearlessness in the Aye-aye; some accounts tell of individual animals strolling nonchalantly in village streets or even walking right up to naturalists in the rainforest and sniffing their shoes. Therefore, it is no wonder that displaced animals often raid coconut plantations or steal food in villages. It is not unlike the American raccoon in this regard.

However, public contempt goes beyond this. The Aye-aye is often viewed as a harbinger of evil and killed on sight. Others believe that should one point its long middle finger at you, you were condemned to death. Some say the appearance of an Aye-aye in a village predicts the death of a villager, and the only way to prevent this is to kill the Aye-aye. The Saklava people go so far as to claim Aye-ayes sneak into houses through the thatched roofs and murder the sleeping occupants by using their middle finger to puncture the victim's aorta.

Incidents of Aye-aye killings increase every year as its forest habitats are destroyed and it is forced to raid plantations and villages. Because of the superstition surrounding it, this often ends in death. Fortunately, the superstition prevents people from desiring to hunt them for food.

Classification

ORDER PRIMATES
- Suborder Strepsirrhini: non-tarsier prosimians
  - Infraorder Lemuriformes
  - Infraorder Chiromyiformes
    - Family Daubentoniidae
      - Genus Daubentonia
        Aye-aye, Daubentonia madagascariensis
        (Daubentonia robusta, extinct)
  - Infraorder Lorisiformes

References

Listed as Endangered (EN A2cd, C2a v2.3)

External links

ARKive - images and movies of the aye-aye (Daubentonia madagascariensis)
Bagheera: an educational website about endangered animals.
Primate Info Net Daubentonia Factsheets
Japan Aye-Aye Fund - a photo of an aye-aye eating a ramie nut
U.S. Fish & Wildlife Service Species Profile

Prosimians | Fauna of Madagascar

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