Scientific name:Indri indri

PHYSICAL DESCRIPTION: Differences between males and females are not significant. Wt. 10 kg.,Ht. 4 ft from head to toe. This makes them the largest of the extant prosimians. Coat: varies considerably, but usually black, white and gray. Brain: an elongated face, which constricts the cranium to surround their relatively small brains. Locomotion: vertical clingers and reapers. They have enlarged vertebrae, which allows them to maintain a vertical posture throughout a leap. A short, rudimentary tail. GEOGRAPHIC LOCATION: They inhabit the eastern rainforests of Madagascar. ECOLOGY: An estimated population density 9-15 animals per Km2. Home range: 18 hectacres. Day range: 50 in outside the perimeter of their home range. They are diurnal and arboreal. They have been observed to move between 300 and 700 m daily within their home range. 50-60% more active in the summer.

DIET: Primarily folivorous, but are also fruigivorous. . A low biomass of I Kg per hectacre. Approximately 10 species of plants make up a majority of their diet. Young leaves and buds: 50-75%. Fruits: 25%. Mature leaves: less than 1%. They have been observed to occasionally eat earth. Tooth scraper: used to scoop fruit pulp.

SOCIAL ORGANIZATION: Monogamous. An average group size of 2-5, usually made up of an adult pair and their young. Females and young form a group and sexually maturing males roam. Adult males remain with the female if it proves to be reproductively successful. Female dominance. Group progressions are typically led by females while the males bring up the rear. They are very territorial, but there is little physical confrontation, because of their effective calling system. Males practice urine marking and females practice anogenital marking.

INTELLIGENCE: One of the best reapers, due to their very long legs. Their vocal system is very effective.

REPRODUCTION: Sexual maturity at 36 months. Gestation period: estimated at 2 months. No estrus swelling. One infant is produced, with an interbirth interval of up to 3 years PARENTAL CARE: Infants carried ventrally for 4-5 months, after which time they are carried dorsally until 7 or 8 months of age. TOPICS OF SPECIAL INTEREST: The most vocal of all lemurs. Produce loud cafls on 2 out of every 3 days, which last from 1-5 minutes.


Clutton-Brock, T.H. 1977. Primate Ecology: Studies of feeding and ranging behavior in lemurs, monkeys and apes. New York: Academic Press Inc.

Devore, 1. 1965. Primate Behavior: Field studies of monkeys and apes. New York: Holt, Rinehart and Winston.

Doyle, M. 1979. The Study of Prosimian Behavior. New7Y6fk@ Acadenu'c-- - Press Inc.

Jolly, A. 1985. The Evolution of Primate Behavior. second edition. New York: Macmillan Publishing Company.

Shapiro, L. 1995. Functional morphology indrid lumbar vertebrae.American Journal of Physical Anthropology 98:323-342.

| Concepts | Glossary | Primate Facts |
| Course Calendar | Assignments, Quizzes, Announcements | Course Home |
<< back to Mark Flinn Teaching