Animal Info - Aye-aye

(Other Names: Ahay, Aiay, Fingertier, Hay-hay)

Daubentonia madagascariensis

Status: Endangered

1. Profile (Picture)
2. Tidbits
3. Status and Trends (IUCN Status, Countries Where Currently Found, Population Estimates, History of Distribution, Threats and Reasons for Decline)
4. Data on Biology and Ecology (Size and Weight, Habitat, Age to Maturity, Gestation Period, Birth Season, Birth Rate, Early Development, Maximum Age, Diet, Behavior, Social Organization, Home Range Size)
5. References

Profile

Pictures: Aye-aye #1 (17 Kb JPEG); Aye-aye #2 (18 Kb JPEG)

The aye-aye has coarse, shaggy black fur with a mantle of white guard hairs. It is a medium-sized nocturnal lemur weighing about 3 kg (6.6 lb). The aye-aye is found in a variety of forest types in Madagascar. Its varied diet includes insect grubs, fruits, nuts, nectar, seeds and fungi. It is also known to raid coconut plantations. The aye-aye is a nocturnal forager. Most of the night is spent traveling and foraging in the upper canopy. The day is spent sleeping in a nest constructed in a tree from interwoven twigs and dead leaves. Large trees may contain as many as six nests. Although the aye-aye is generally solitary, males and females occasionally come together outside of breeding periods and interact briefly, often when foraging. Both males and females may mate with several partners.

The aye-aye formerly inhabited much of the coastal area of eastern and northwestern Madagascar. By 1983 only a few scattered individuals were thought to remain on the northeast and possibly northwest coasts. However, sightings increased during the 1980's, and by 1994 it had been reported from an increasing number of locations, although always at low densities.

Loss of forest habitat is the main threat to the aye-aye. It also is killed by some native people due to superstitious beliefs.

Tidbits

*** The aye-aye is the largest nocturnal primate in the world (Macdonald 1984).

*** The aye-aye displays an unusual degree of fearlessness towards humans. Wild aye-ayes have been known to stroll nonchalantly down a village street in Madagascar or appear unexpectedly from nowhere in the rainforest to sniff a researcher's shoes. (Haring 1996)

*** In some parts of Madagascar, the aye-aye is regarded as a harbinger of evil and killed on sight (The Sakalava believe that the aye-aye enters houses during the night through thatched roofs and murders the sleeping human occupants. It supposedly uses its elongated finger to cut the aortic vein of its victims. (Goodman & Schütz 2000)). In other parts of Madagascar the aye-aye is considered to be a good omen.

*** The aye-aye is different from the other lemurs because it is highly specialized in many ways; among them are its unique dental formula (distinct from all other primates), its continuously growing incisor teeth (which led to its being considered a rodent during part of the 19^th century), its large ears (almost certainly used in locating insect larvae in dead wood), and its long skeleton-like middle finger used to extract larvae from holes. So unique is it among the lemurs that it has proven extremely difficult to determine which other lemurs are its closest relatives. The aye-aye is so unusual that it is not only strange within the context of the primates, it is one of the most distinctive mammals on earth. (Mittermeier et al. 1994)

Status and Trends

IUCN Status

1960's - 1994: Endangered
1996 - 2004: Endangered (Criteria: A2cd, C2a) (IUCN 2004)

Countries Where the Aye-aye Is Currently Found:

2004: Occurs in Madagascar (IUCN 2004).

Population Estimates:

[Note: Figures given are for wild populations only.]

WORLD (Madagascar)
- 1965: 12 - 20 (Curry-Lindahl 1972)
- 1967: 50 or less (IUCN 1967)
- 1974: Not more than about 50 (Fitter 1974)
- 1994: Although no population figures are available, an order of magnitude estimate would be 1000 - 10,000 (Mittermeier et al. 1994)

History of Distribution:

The aye-aye formerly inhabited much of the coastal area of eastern and northwestern Madagascar. It occurred among the coastal rain forests of northeast Madagascar and in a smaller area on the northwest coast until the 1960's, but as of 1972 its population was believed to be much reduced in size and concentrated in three isolated areas. Its last forest localities known at the time were destroyed in 1965, causing the few remaining animals to invade plantations. By 1983 only a few scattered individuals were thought to remain on the northeast and possibly northwest coasts of Madagascar. However, sightings increased during the 1980's, and by 1994 it had been reported from an increasing number of locations, including along the entire east coast as well as Antsiranana and Mahajanga provinces. It has only been recorded at low densities in all the localities where it has been found.

A number of individuals have been captured and released on the island of Nosy Mangabe, a protected reserve off the northeast coast of Madagascar.

Threats and Reasons for Decline:

The main threat to the aye-aye comes from loss of its forest habitat.

Traditionally, indigenous people on Madagascar tolerated the aye-aye, and even regarded it with superstitious awe. However, attitudes have changed and now the aye-aye is regarded by some as a harbinger of death. The appearance of one in the vicinity is thought by some people to signify the imminent death of a villager, with the only way of averting this being to kill the aye-aye. When loss of its forest habitat led the aye-aye to invade plantations, animals were killed when they raided villagers' crops. Fortunately, because of its evil reputation it is usually not hunted for food.

Data on Biology and Ecology

Size and Weight:

The head and body length of the aye-aye is about 30 - 37 cm (12 - 15"). The tail is about 44 - 53 cm (17 - 21") long. It weighs 2 - 3 kg (4.4 - 6.6 lb).

Habitat:

The aye-aye has been found to be widely distributed in a variety of native forest types. It has been recorded at localities covering the entire extent of the eastern rainforest belt and in the moist forests of the Sambirano region in the northwest, the drier forests to the south in the vicinity of the Manasamody hills, the deciduous forests of Ankarana and Analemera, the rainforests of Montagne d’Ambre in the far north, and some cultivated areas like coconut and lychee nut plantations. (Garbutt 1999) Locations where it is sighted are often below 700 m (2300'). However, it has been observed at an altitude of 800 m (2600') and evidence of its feeding has been observed at 1250 m (4100') (Goodman & Schütz 2000).

The aye-aye lives in the Madagascar & Indian Ocean Islands Biodiversity Hotspot (Cons. Intl. 2005).

Age to Maturity:

Probably more than 2 years for females and more than 1 year for males.

Gestation Period:

160 - 170 days (Garbutt 1999).

Birth Season:

Births can occur at any time throughout the year.

Birth Rate:

A single offspring is generally produced. There are indications that females have a 2 - 3 year interval between births. (Garbutt 1999)

Early Development:

Baby aye-ayes are weaned at about 7 months. A young aye-aye stays with its mother for about 2 years.

Maximum Age:

23 years (captivity).

Diet:

The aye-aye is specialized as a night-time primate "woodpecker." It taps trees with its long middle finger, listens intently with its huge ears for wood-boring grubs under the bark, exposes them by gnawing with its rodent-like, ever-growing front teeth, and extracts them with its middle finger. The aye-aye also eats fruits, nuts, nectar, seeds and fungi. It is known to raid coconut plantations and has been seen eating lychee nuts and mangoes. (Garbutt 1999, Macdonald 2001)

Behavior:

The aye-aye is a nocturnal forager. Activity begins between 30 minutes before and 3 hours after sunset. Up to 80% of the night is spent traveling and foraging in the upper canopy. The foraging activities are separated by rest periods that may last up to 2 hours. The aye-aye is able to move quite nimbly around the branches and can leap and climb vertically with ease. Horizontal movements are more deliberate, but it does descend to the ground and sometimes covers large distances. Males are capable of traveling between 2 - 4 km (1.2 - 2.4 mi) in a single night. (Garbutt 1999)

The day is spent sleeping in a nest constructed in a tree from interwoven twigs and dead leaves, usually towards the canopy (above 7 m (23')) in a dense tangle of vines or branches. In one study, 8 aye-ayes used over 100 nests in a 2 year period, with different aye-ayes using the same nest on different occasions. Large trees may contain as many as six nests. (Garbutt 1999)

Social Organization:

Home ranges of males can overlap considerably with one another, and the common area may be occupied by both males simultaneously. Interactions occur and are sometimes antagonistic. Female home ranges do not overlap with one another. Females rarely interact, but when they do, they are invariably aggressive towards one another. Female home ranges do overlap with the home range of at least one male. Both males and females may mate with several partners. Outside of breeding periods, males and females occasionally come together and interact briefly, often when foraging. When they are active, aye-ayes scent-mark regularly through urination and also by rubbing their ano-genital region, neck and cheeks on branches. (Garbutt 1999)

Home Range Size:

Male aye-ayes have large home ranges, between 100 - 200 hectares (250 - 500 acres). Females' home ranges are much smaller, generally between 30 - 50 hectares (75 - 150 acres). (Garbutt 1999)

References

Burton & Pearson 1987, Cons. Intl. 2005, Curry-Lindahl 1972, Fitter 1974, Garbutt 1999, Goodman & Schütz 2000, Haring 1996, IUCN 1967, IUCN 1994, IUCN 1996, IUCN 2000, IUCN 2003a, IUCN 2004, Macdonald 1984, Macdonald 2001, Mittermeier et al. 1994, Nowak & Paradiso 1983, Oryx 1964, Oryx 1967b

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Last modified: March 7, 2005;