Allocebus trichotis
hairy-eared dwarf lemur

Hairy-eared dwarf lemurs, Allocebus trichotis, are unquestionably among the rarest of surviving lemurs, and presumably have never existed in high numbers. Allocebus trichotis had not been seen in over 20 years when, in March 1989, it was rediscovered in the vicinity of the Mananara River in northeastern Madagascar, which is its exclusive habitat. Until its rediscovery, it was only known from five museum specimens. Its distribution on the island is isolated to the northeastern portion, 16°12’S, 49°37’E through 16°28’S, 49°38’E. (Albignac and Meier, 1991)

Little in known about the habitat preferences of A. trochotis, but it appears to occur mainly in lowland primary forest. This species is found at elevations between 680 and 1235 m. (Albignac and Meier, 1991)

Allocebus trichotis has an average head and body length of 133 mm and an average tail length of 170 mm. Mass ranges between 70 and 100 g, with an average of 85 g. Males and females are similar in size and coloration.

The dorsal surface of these animals is brownish gray, the underparts are whitish gray, and the tail is reddish brown. The ears are short, with tufts of long hair in front and on the internal side of the lobe, hence the common name Hairy-eared Dwarf Lemur.

This species has teeth like Phaner fucifer (forked-crown lemurs), but the teeth are unique in that the second and third upper molars are caniniform and the first upper incisor is enlarged. On the digits the nails are keeled, not pointed.

Hairy-eared dwarf lemurs have a relatively long tongue compared to Microcebus and Cheirogaleus. (Albignac and Meier, 1991)

There are no data on lifespan or longevity for this species. However, other members of the family Cheirogaleidae are noted to live 15 to 19 years in captivity. Allocebus trichotis is probably similar. (Nowak, 1999)

Allocebus trichotis is a nocturnal species, becoming active at dusk and remaining so until dawn, and is primarily arboreal. Allocebus trichotis makes nests of fresh leaves in small holes in either living or dead trees, usually 3 to 5 meters above the ground. Local people report that up to six animals may sleep together, both male and female plus juveniles. The basic group of hairy-eared dwarf lemurs is comprised of an adult pair and their offspring. They have been reported to hibernate, becoming torpid in trees or under leaf litter at the base of a tree from May to September. During this torpid season A. trichotis utilizes fat distributed across the body and stored for this purpose (Charles-Dominique et al, 1980).

Mated pairs groom one another, removing dead skin and parasites. In captive hairy-eared dwarf lemurs it was found that males and females groom each other before they leave the nest at night (Nowak, 1999). (Albignac and Meier, 1991; Charles-Dominique et al., 1980; Nowak, 1999)

Home Range

The size of the home range used by these animals is not known.

Specific patterns of communication have not been reported for A. trichotis. However, if this species is like other primates, some combination of vocal communication, body postures, and tactile communication are used in interacions with conspecifics. These aniamls may also use chemical communication. (Nowak, 1999)

No data are available detailing what A. trichotis eats in the wild. Allocebus trichotis has large upper incisors, like those of Phaner, and may use these teeth to scrape tree bark to obtain exudates or plant gum, as does Phaner species. In captivity, 50 to 70% of the diet consists of small to medium sized locusts, which are caught by jumping on them and grasping them with both hands. These actions are very stereotypical and look as if they may be part of a fixed action pattern.

In addition to insects, A. trichotis may be adapted to eating nectar. The animal has an extraordinarily long tongue and readily ate honey while in captivity (Nowak, 1999). (Albignac and Meier, 1991; Nowak, 1999)

Allocebus trichotis functions very well in its arboreal environment. With its small size it is able to out-climb most predators. Although data on predation rates are not available, likely predators include Malagasy carnivores (Eupleridae), owls, and humans.

If A. trichotis feeds on nectar, as has been suggested, this species may play some role in plant pollination. These animals may also act to control insect populations somewhat. To the extent that they serve as prey items, these animals may impact predator populations.

There are no known adverse affects of A. trichotis on humans.

Hairy-eared dwarf lemurs are reportedly eaten regularly by the local people of Northeastern Madagascar.

Little is known about the conservation status of A. trichotis, because individuals of this species are extremely hard to locate. Since 1875, biologists have observed speciments only twice--in 1966 and 1989. It is certain that the rapid deforestation and destruction of habitat are the main contributing factors to the decline of A. trichotis. Efforts of the Malagasy government are now underway to protect one of the last portions of virgin lowland rainforest in Northeastern Madagascar. This action and continuing research are vital to study the conservation status and basic biology of this species in the wild. (Albignac and Meier, 1991; Harcourt, 1990; Nowak, 1999)

Most lemurs on the island of Madagascar are endangered. Rapid deforestation and the exponential growth rate of humans gives these species little room. Hairy-eared dwarf lemurs are at particular risk and are classified as endangered by CITES. Populations of A. trichotis are severely fragmented and are known to exist in no more than 5 locations. Habitat preservation is needed to aid the survival of this species and all others on the island of Madagascar.