Avahi lanigeravahi(Also: woolly lemur)

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Geographic Range

Woolly lemurs are found only on the northwest and eastern sides of the island of Madagascar, off the southern coast of Africa.

(Harcourt and Thornback, 1990; Wolfheim, 1983) (Harcourt and Thornback, 1990; Wolfheim, 1983)

Habitat

Avahi laniger is found in tropical regions. The population found in western Madagascar (A. laniger occidentalis) occupy dry seasonal forest where the elevation varies. In east Madagascar, A. laniger laniger occurs in a humid coastal forest at lower elevations.

(Flannery, 2000; Nowak, 1991; Parker, 1990) (Nowak, 1991; Parker, 1990; Wisconsin Regional Primate Research Center, University of Wisconsin - Madison, 2001)

  • Range elevation
    800 to 2000 m
    2624.67 to 6561.68 ft

Physical Description

Avahi laniger typically weighs between 600 and 1,300 g. Head and body length varies between 300 and 450 mm.

Woolly lemurs are typically grey-brown or reddish-brown in color, but color varies within the species. Th forearms, hands, legs, and feet are white and the tail is reddish-orange. The fur is thick and woolly (hence the common name), unlike other members of the family Indriidae, which have silky fur. Woolly lemurs have a spherical face which is covered in short hairs, their small ears are concealed within the woolly fur. Avahi laniger has large eyes and a short snout, and a characteristic white stripe that goes up the thigh. Sexes are similar, and it is nearly impossible to distinguish between males and females from a distance, though males have slightly larger molars and skulls. The lower incisors of woolly lemurs are modified into comb-like structure.

(Nowak, 1991; Parker, 1990) (Nowak, 1991; Parker, 1990)

  • Sexual Dimorphism
  • male larger
  • Range mass
    600 to 1300 g
    21.15 to 45.81 oz
  • Range length
    300 to 450 mm
    11.81 to 17.72 in

Reproduction

Like many mammals on Madagascar, male and female A. laniger seem to mate for life. Couples stay together, raise their young, and live as a family.

(Parker, 1990) (Parker, 1990)

Breeding occurs from March to May, followed by a gestation of approximately 135 days. Infant woolly lemurs are born during August and September and develop slowly. The baby stays with its mother and is weaned the following wet season. The time to weaning averages 6 months. Other members of the family Indriidae become independent after about 2 years of age.

(Nowak, 1991; Jolly, 1984)

  • Breeding interval
    These interbirth interval of these animals is not known.
  • Breeding season
    Breeding occurs from March to May.
  • Range number of offspring
    2 (high)
  • Average number of offspring
    1
  • Range gestation period
    120 to 150 days
  • Range weaning age
    8 to 12 months
  • Average weaning age
    6 months

Although it is the mother that does most of the care for infant woolly lemurs, the father stays close by. Males have never been seen with a clinging infant.

Infants are dependent upon the mother until they are fully capable of feeding and traveling on their own. From birth to about 2 months, the infant is carried crosswise on the mothers' front side, and nurses 3 to 4 times a day in lengthy sessions. The mother situates herself in a comfortable position to settle down for an afternoon nap and feed her young. As the infant gets older, it moves from being carried on the front to the back and then begins to slowly venture away from the mother.

Feeding behavior begins incidental to play. Young begin playing with the food that the mother is eating, and casually gnaw on the twig or fruit. Thus they gradually learn which foods are safe and good to eat.

At this age, infants become more aware of the surrounding environment by grasping onto nearby branches. By 6 months, the now-weaned infant learns to leap from branch to branch following its mother. Infants do occasionally fall, sometimes up to 30 feet. In a few more months, they learn how to judge distances and make difficult leaps. At one year of age infant woolly lemurs become independent, although the mother is still close by. Even at 2 years of age, the relationship between mother and child is relatively close.

(Harcourt, 1991; Jolly, 1984; Nowak, 1991) (Harcourt, Apr 1991; Jolly, et al., 1984; Nowak, 1991)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
    • protecting
      • female
  • post-independence association with parents
  • extended period of juvenile learning

Lifespan/Longevity

Little is known about the lifespan of A. laniger. They are reportedly unsuccessful in zoos, living no longer than three months in captivity outside of Madagascar. However, other members of the family Indriidae are reported to live over 23 years in captivity. It is reasonable to assume that A.laniger has a similar potential lifespan.

(Parker, 1990; Tattersol and Sussman, 1975; Nowak, 1991) (Nowak, 1991; Parker, 1990; Tattersol and Sussman, 1975)

  • Typical lifespan
    Status: captivity
    few (low) months

Behavior

Woolly lemurs are nocturnal. They use vertical clinging and leaping as a means of locomotion. When they descend from trees, they stand erect and leap with both feet together holding their arms up in the air much like other lemurs and sifakas.

Because of the low nutritive value of their diets, woolly lemurs are unable to maintain high levels of energy. These lemurs spend long periods of time sleeping. They are highly social animals, forming particularly close and long-lasting family ties.

(Harcourt, 1991; Nowak, 1991) (Harcourt, Apr 1991; Nowak, 1991)

Home Range

Group ranges of eastern woolly lemurs (A. laniger laniger) are 1 to 2 ha in size and do not overlap, indicating some degree of territoriality. This is not the case in western woolly lemurs (A. laniger occidentalis), where home ranges may reach 4 ha. (Harcourt, Apr 1991; Nowak, 1991)

Communication and Perception

As in other primates, it is likely that these animals use a variety of modalities of communication. Vocal communication has been reported. In addition, tactile communication, especially within the family unit, is expected. Visual communication, in the form of body postures and gestures probably also occurs.

Food Habits

The diet of A. laniger is very similar to that of the closely related species Indri indri. The two species are able to live in the same area and share the same diet because they have different activity periods. Avahi laniger is active at night, whereas I. indri is a diurnal species. Although woolly lemurs have been known to eat flowers and fruits, their diet consists mainly of young leaves. They eat only the leaf blade, leaving the midrib and petiole behind.

One male A. laniger studied by Harcourt (1991) made some interesting feeding actions. The male often went to the end of a branch to pick leaves, then returned to the main trunk to eat them. He was also seen eating bits off leaves that remained attached to the tree.

(Cowlishaw & Dunbar, 2000; Harcourt, 1991)

Avahi laniger eats the leaves, buds, and twigs of: Harongana, Hafotra malady, Bararata, Hafidahy, Varongy, Voara, Herodrano, Fatsikahitra, Tavolarano petite feuille, Tavolomalady, Malambovany, Rotra madinika, Rahiaka, Mahanoram, Sary, Karambitoma, Rotra and Fohaninasity. (Cowlishaw and Dunbar, 2000; Harcourt, Apr 1991)

  • Plant Foods
  • leaves
  • fruit
  • flowers

Predation

Woolly lemurs are small and secretive, protecting them from some predators. Their primary wild predators are Henst's goshawks, which find them while resting on exposed branches during the day.

(Flannery, 2000; Harcourt & Thornback, 1990; Wolfheim, 1983) (Harcourt and Thornback, 1990; Wisconsin Regional Primate Research Center, University of Wisconsin - Madison, 2001; Wolfheim, 1983)

Ecosystem Roles

Woolly lemurs act as a prey species for several predators, including humans. Through its folivory, A. laniger may influence plant composition in the forests where they live.

(Flannery, 2000) (Wisconsin Regional Primate Research Center, University of Wisconsin - Madison, 2001)

Economic Importance for Humans: Positive

Although A. laniger is an endangered species, it is still hunted for food by Malagasy people.

(Harcourt & Thornback, 1990) (Harcourt and Thornback, 1990)

  • Positive Impacts
  • food

Economic Importance for Humans: Negative

None known

Conservation Status

Woolly lemurs are a species of great concern in conservation efforts, as are many other species in the Lemuridae and Indriidae families. This concern is mainly due to the considerable amount of habitat loss in Madagascar's tropical rainforests. Although this island known for extraordinary levels of endemic biodiversity and conservationists are working hard to protect lemur species, habitat loss and the hunting of lemurs for food continues at a rapid pace.

(Harcourt & Thornback, 1990; Nowak, 1991) (Harcourt and Thornback, 1990; Nowak, 1991)

Other Comments

There are two subspecies of A. laniger: Avahi laniger laniger is found in eastern Madagascar, and A. laniger occidentalis is found in northwestern Madagascar. The two subspecies are so similar that some researchers do not consider them to be distinct, though some behavioral differences have been noted.

(Flannery, 2000; Tattersall & Sussman, 1975) (Tattersol and Sussman, 1975; Wisconsin Regional Primate Research Center, University of Wisconsin - Madison, 2001)

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Pam Ehler (author), University of Northern Iowa, Jim Demastes (editor), University of Northern Iowa.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fertilization

union of egg and spermatozoan

folivore

an animal that mainly eats leaves.

food

A substance that provides both nutrients and energy to a living thing.

herbivore

An animal that eats mainly plants or parts of plants.

island endemic

animals that live only on an island or set of islands.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Cowlishaw, G., R. Dunbar. 2000. Primate Conservation Biology. Chicago: University of Chicago Press.

Harcourt, C. Apr 1991. Diet and Behavior of a Nocturnal Lemur, *Avahi laniger*, in the Wild. Journal of Zoology, 223: 667-74.

Harcourt, C., J. Thornback. 1990. Lemurs of Madagascar and the Comoros: The IUCN Red Data Book. Cambridge, U.K.: IUCN.

Jolly, A. Aug. 1988. Madagascar's Lemurs, On the Edge of Survival. National Geographic, 174: 138.

Jolly, A., P. Oberle, R. Albignac. 1984. Key Environments: Madagascar. New York: Pergamon Press.

Nowak, R. 1991. Walker's Mammals of the World (5th Edition). Baltimore: The Johns Hopkins University Press.

Parker, S. 1990. Grzimek's Encyclopedia of Mammals. New York: McGraw-Hill.

Tattersol, I., R. Sussman. 1975. Lemur Biology. New York: Plenum Press.

Wisconsin Regional Primate Research Center, University of Wisconsin - Madison, 2001. "Primate Info Net, Eastern Woolly Lemur (Avahi laniger)" (On-line). Accessed Jan. 7, 2002 at http://pin.primate.wisc.edu/factsheets/avahi_laniger.html.

Wisconsin Regional Primate Research Center, University of Wisconsin - Madison, 2001. "Primate Info Net, Western Woolly Lemur (Avahi occidentalis)" (On-line). Accessed Jan. 7, 2002 at http://pin.primate.wisc.edu/factsheets/avahi_occidentalis.html.

Wolfheim, J. 1983. Primates of the World: Distribution, Abundance, and Conservation. Seattle: University of Washington Press.