Family: Daubentoniidae
The aye-aye’s continuously growing incisor teeth led to it being classified as a rodent during part of the 19th century. It was not until around 1850 that the species was widely accepted as a primate. Lemurs belong to the suborder Strepsirhini, which also includes bushbabies, pottos and lorises. These groups are the most basal living primates. Ancestral prosimians, possibly resembling today’s mouse lemurs, are thought to have colonised Madagascar from mainland Africa 50-60 million years ago. In the absence of competition from other non-primate mammals, these species diversified to fill a wide range of unusual ecological niches. There are five distinct families of lemurs: Lemuridae, Indriidae, Megaladapidae, Cheirogaleidae and Daubentoniidae. The aye-aye is the most evolutionarily distinct of all the lemurs, being the only living representative of an entire family of primates (Daubentoniidae). It is so unique that it has proved difficult to determine which other lemurs are its closest relatives, although some researchers have suggested that it is most closely related to the indriids. Remains of a second, extinct species of aye-aye (Daubentonia robusta) are known from a few sites in southern Madagascar. This species is thought to have been up to five times heavier than the living species, and was probably driven to extinction by human activities.
Size:
Head and body length: 360-440 mm
Tail length: 500-600 mm
Tail length: 500-600 mm
Weight: 2-3 kg
The highly distinctive aye-aye is the world’s largest nocturnal primate. It has a thick coat of coarse black or brown hair flecked with white from longer guard hairs, and a long bushy tail which more than doubles the length of the body. The species has a number of extreme morphological adaptations to its unusual feeding habits, making it one of the most bizarre-looking animals on the planet. It has huge, leathery bat-like ears and prominent yellowish-orange eyes. The fingers are long and narrow and tipped with curved claw-like nails. The third finger on each hand is skeletal in appearance. It is extremely long and thin, and is primarily used for extracting insect larvae from holes in trees.
A nocturnal species, the aye-aye spends its days sleeping in an elaborate nest of intertwined twigs and dead leaves. These nests can take up to 24 hours to construct, and are often located high up in the crowns of tall trees. As they move from place to place individuals either build new nests or make use of those constructed by other aye-ayes. Male aye-ayes have large overlapping ranges of around 100 to 200 ha, which usually contain several females. The home ranges of females are smaller and do not overlap. Individuals mark their ranges with urine and scent from glands in their necks, cheeks and rumps. Breeding is thought to occur throughout the year, with females advertising their readiness to mate through distinctive calls. They are thought to give birth to a single young every two to three years. Although regarded as a generally solitary species, males and female aye-ayes have been observed foraging together outside of breeding periods.
Aye-ayes appear to have evolved to fill the niche occupied by woodpeckers and squirrels in other parts of the world (neither of these occur in Madagascar). They can locate grubs living in cavities under tree-bark by tapping their skeletally thin middle fingers on the branch and listening to the reverberations through the wood. Once a promising cavity has been found the aye-aye cocks forward its large ears and listens for the sound of grubs burrowing beneath the bark. If a grub is heard the aye-aye will rip open the cavity with its teeth and hook out the grub with its middle finger. Aye-ayes also eat fruit, nuts, nectar, seeds and fungi. Their sharp teeth and long middle fingers enable them to extract flesh from hard fruits such as coconuts and ramy nuts (Canarium madagascariensis).
Aye-ayes appear to have evolved to fill the niche occupied by woodpeckers and squirrels in other parts of the world (neither of these occur in Madagascar). They can locate grubs living in cavities under tree-bark by tapping their skeletally thin middle fingers on the branch and listening to the reverberations through the wood. Once a promising cavity has been found the aye-aye cocks forward its large ears and listens for the sound of grubs burrowing beneath the bark. If a grub is heard the aye-aye will rip open the cavity with its teeth and hook out the grub with its middle finger. Aye-ayes also eat fruit, nuts, nectar, seeds and fungi. Their sharp teeth and long middle fingers enable them to extract flesh from hard fruits such as coconuts and ramy nuts (Canarium madagascariensis).
Found in a variety of habitats including primary and secondary rainforest, deciduous forest, dry scrub forest, and cultivated areas.
Endemic to Madagascar, the species was previously believed to be highly restricted and nearly extinct. It is now known to occur at low densities throughout the eastern rainforest belt as well as in the dry forests of the northwest and west of the island.
The current size of the aye-aye population is unknown. An order of magnitude estimate for the species would be 1,000-10,000 individuals.
Classified as Endangered (EN A2cd, C2a) on the 2006 IUCN Red List of Threatened Species.
Habitat loss is the main threat to the continued survival of the aye-aye. The forests in which it lives are being cleared to make way for agriculture and development. Since the species occurs at low densities, large tracts of forest are required to sustain viable populations. The loss of its forest habitat has led the aye-aye to invade plantations and raid crops such as coconuts and lychees, bringing it into conflict with villagers, who often kill it as a crop pest. Local superstitious beliefs have also played a role in the decline of the species. In some areas aye-ayes are thought to embody the ancestral spirits and bring good luck. However, elsewhere they are regarded as harbingers of death and killed upon sight. The species is rarely hunted for food because of its evil reputation.
The species is listed on Appendix I of CITES. It is known to occur in at least 16 protected areas within Madagascar, although many of these reserves require better protection. In 1966 nine aye-ayes were introduced to Nosy Mangabe Special Reserve, an island off the northeast coast of Madagascar, in the hope of establishing a breeding colony to safeguard against extinction on the mainland. Aye-ayes have been bred in captivity at the Duke Primate Center, and the Durrell Wildlife Preservation Trust (Jersey Zoo). There are also breeding pairs at London Zoo, Bristol Zoo, Paris Zoo and Tokyo Zoo. There are currently around 45 aye-ayes in captivity. A European Endangered Species Programme (EEP) was created for the species by Durrell Wildlife in January 2005 to effectively manage the captive population.
Further surveys are needed to assess the status and distribution of the aye-aye both within and outside of protected areas. Many of these areas are in need of better protection. Further research and monitoring of wild populations is also recommended. Laws against killing aye-ayes need better enforcement, and should be coupled with public awareness campaigns to discourage the killing of aye-ayes. A programme to compensate farmers for damage to crops caused by aye-ayes may also be beneficial.
Madagascar Fauna Group (MFG)
MFG is an international collaboration of zoos and related organizations that work together to conserve one of the worlds most endangered regions in the world. MGF works closely with AZA and aims to sustain the high levels of unique biodiversity and protect the many endemic species of Madagascar.
Duke Lemur Center
The Duke Lemur Center based at Duke University aims to promote research and understanding of prosimians and their natural habitat as a means of advancing the frontiers of knowledge. Research is geared towards contributing to the educational development of international conservation and to enhance the sustaining of global biodiversity. The Duke Lemur Center is funded by the National Science Foundation, Duke University and private donors.
Durrell Wildlife Conservation Trust
Durrell Wildlife Conservation Trust is an organisation born out of the passion of conservationist Gerald Durrell’s desire to help endangered species worldwide. DWCT has species links with research in Madagascar and is actively involved in many conservation breeding programmes. The Trust has well-established links with the Malagasy people and government, especially involving the conservation of lemurs, and is part of the Madagascar Fauna Group
MFG is an international collaboration of zoos and related organizations that work together to conserve one of the worlds most endangered regions in the world. MGF works closely with AZA and aims to sustain the high levels of unique biodiversity and protect the many endemic species of Madagascar.
Duke Lemur Center
The Duke Lemur Center based at Duke University aims to promote research and understanding of prosimians and their natural habitat as a means of advancing the frontiers of knowledge. Research is geared towards contributing to the educational development of international conservation and to enhance the sustaining of global biodiversity. The Duke Lemur Center is funded by the National Science Foundation, Duke University and private donors.
Durrell Wildlife Conservation Trust
Durrell Wildlife Conservation Trust is an organisation born out of the passion of conservationist Gerald Durrell’s desire to help endangered species worldwide. DWCT has species links with research in Madagascar and is actively involved in many conservation breeding programmes. The Trust has well-established links with the Malagasy people and government, especially involving the conservation of lemurs, and is part of the Madagascar Fauna Group
ARKive. (Jan 2006).
Durrell Wildlife Trust: the aye-aye. (Jan 2006).
Ganzhorn, J. & Members of the Primate Specialist Group. 2000. Daubentonia madagascariensis. In: IUCN 2006. 2006 IUCN Red List of Threatened Species. Downloaded on 09 August 2006.
Garbutt, N. 1999. Mammals of Madagascar. Pica Press. East Sussex.
Mittermeier, R. A. et al. 1994. Lemurs of Madagascar. Conservation International. Washington, DC.
Nowak, R. M. 1999. Walker’s Mammals of the World. Sixth edition. The Johns Hopkins University Press. Baltimore and London.
Simons, E. L. and Meyers, D. M. 2001. Folklore and Beliefs about the Aye aye (Daubentonia madagascariensis). Lemur News 6: 11-16
Distribution map based on data provided by the IUCN Global Mammal Assessment.
Durrell Wildlife Trust: the aye-aye. (Jan 2006).
Ganzhorn, J. & Members of the Primate Specialist Group. 2000. Daubentonia madagascariensis. In: IUCN 2006. 2006 IUCN Red List of Threatened Species. Downloaded on 09 August 2006.
Garbutt, N. 1999. Mammals of Madagascar. Pica Press. East Sussex.
Mittermeier, R. A. et al. 1994. Lemurs of Madagascar. Conservation International. Washington, DC.
Nowak, R. M. 1999. Walker’s Mammals of the World. Sixth edition. The Johns Hopkins University Press. Baltimore and London.
Simons, E. L. and Meyers, D. M. 2001. Folklore and Beliefs about the Aye aye (Daubentonia madagascariensis). Lemur News 6: 11-16
Distribution map based on data provided by the IUCN Global Mammal Assessment.
No comments:
Post a Comment