By Alexis Zenner
Geographic Range
Red-bellied lemurs, Eulemur rubriventer, live in the eastern rainforest zone of Madagascar (Nowak, 1999). (Nowak, 1999)
Other Geographic Terms:
island endemic 
.
Habitat
This lemur mainly inhabits rainforest regions, at medium to high altitudes (Macdonald, 1984; Nowak, 1999). (Macdonald, 1984; Nowak, 1999)
These animals are found in the following types of habitat:
tropical ; terrestrial .
Terrestrial Biomes:
rainforest .
Physical Description
(4.4 to 6.6 lbs; avg. 5.5 lbs)
(14.17 to 21.26 in; avg. 17.72 in)
Red-bellied lemurs are sexually dichromatic. Females have white bellies with white markings on the neck and chin, whereas males are mostly brown with dramatic white eye patches and a scent gland located on the forehead. Both sexes both have a black tail.
The head and body length is from 36 to 42 cm and the tail length is 46 to 54 cm. These lemurs usually weigh between 2 and 3 kg and are approximately the size of a house cat (SUNY, 1999; Schmid & Smolker, 1998). (Schmid and Smolker, 1998; Stony Brook State University of New York, 1999)
Some key physical features:
endothermic ; bilateral symmetry .
Sexual dimorphism: sexes colored or patterned differently.
Reproduction
These lemurs are capable of breeding annually.
Mating occurs from May through June with births occuring from September to October.
Red-bellied lemurs are one of the few lemur species to form monogamous pair bonds. These form the core of the social group, which typically consists of the mated pair and their offspring. (Duke University Primate Center, 1999) (Duke University Primate Center, 1999)
Mating systems:
monogamous .
Red-bellied lemurs have a gestation period of 127 days and give birth from September to October. There is usually a single young born, though twins sometimes occur, and birth weight is 60 to 70 grams. An estrous cycle lasts one month and estrous lasts 1 to 2 days (Schmid & Smolker, 1998). Mothers wean their young around the age of 5 months.
Sexual maturity is reached at about 2 years of age. (Duke University Primate Center, 1999)
Key reproductive features:
iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous .
Both male and female parents care for their offspring. The mother nurses and carries the infant for the first 2 weeks of life. From 2 weeks to 5 weeks of age, the young are cared for equally by both parents, although nursing is only accomplished by the mother. After 5 weeks of age, the mother often rejects the young, leaving the father to care for them until they are about 100 days old. (Duke University Primate Center, 1999)
Parental investment:
altricial ; pre-fertilization (provisioning, protecting: female); pre-hatching/birth (provisioning: female, protecting: male, female); pre-weaning/fledging (provisioning: female, protecting: male, female); pre-independence (protecting: male).
Lifespan/Longevity
Red-bellied lemurs live 20 to 25 years in the wild (Duke University Primate Center, 1999).
Behavior
Red-bellied lemurs are mainly diurnal. They are social, living in groups of 5 or fewer individuals, usually consisting of a mated pair and their offspring. Females are dominant over males and lead the group in foraging. Females have preferential access to food and chose their own mates. Red-bellied lemurs do not appear to be territorial. Grooming is an important way of maintaining social cohesion within the group. Lemurs use their lower incisors as a comb to groom troop members (Duke University Primate Center, 1999; Nowak, 1999; Preston-Mafham, 1992).
Key behaviors:
diurnal ; motile ; sedentary ; social ; dominance hierarchies .
Communication and Perception
As in other primate species, communication is complex and occurs in a variety of ways. In addition to vocal communication, E. rubriventer uses chemicals to communicate. The prominent forehead scent gland of males is used to help mark territories. Facial expressions and body postures are some of the visual signals these primates use in communication. Finally, tactile communication, through grooming, mating, play, and aggression, also occurs. (Duke University Primate Center, 1999; Nowak, 1999)
Food Habits
The diet of red-bellied lemurs consists mainly of flowers, fruits and leaves of 67 identified plant species. They also eat some invertebrates. When they eat toxic millipedes, they drool on them first, which may help to neutralize the toxins so these invertebrates are edible. Red-bellied lemurs, as well as other lemur species, may also eat soil (Nowak, 1999; Preston-Mafham, 1992). (Nowak, 1999; Preston-Mafham and Preston-Mafham, 1992)
Animal Foods:
insects.
Plant Foods:
leaves; seeds, grains, and nuts; fruit; flowers.
Predation
- fossa (Cryptoprocta ferox)
- raptors (Falconiformes)
- humans (Homo sapiens)
- domestic dogs (Canis lupus familiaris)
- domestic cats (Felis silvestris)
When feeding, red-bellied lemurs employ a sentinel to keep watch for predators. If a bird of prey or some other predator is detected, the sentinel will utter several low grunts. The other members of the group will either freeze for periods up to 15 minutes or they will take cover. The are preyed upon by fossas (the largest carnivore in Madagascar) and raptors (Preston-Mafham, 1992; Stony Brook State University of New York, 1999). They are also hunted by humans and taken by introduced dogs and cats. (Preston-Mafham and Preston-Mafham, 1992; Stony Brook State University of New York, 1999)
Ecosystem Roles
These lemurs play a role in seed dispersal and germination from seeds contained in the feces (Dew & Wright 1998).
Key ways these animals impact their ecosystem:
disperses seeds.
Economic Importance for Humans: Negative
There are no negative effects of red-bellied lemurs on humans.
Economic Importance for Humans: Positive
Red-bellied lemurs, as well as the other species of lemurs, are charismatic and unique animals, making them valuable for ecotourism. These animals have also been used in behavioral research. They are sometimes hunted for food.
Ways that people benefit from these animals:
food ; ecotourism ; research and education.
Conservation Status
All species in this genus are endangered. The red-bellied lemur is listed as vulnerable by IUCN and is on Appendix I of CITES. Populations are estimated between 10,000 and 100,000 animals, and are thought to be declining due to the rapid loss of rainforest habitat in Madagascar (Nowak, 1999). All members of the Lemuridae are listed as endangered by the U.S. Federal government. (Nowak, 1999)
Other Comments
Rred-bellied lemurs have been used in many behavioral studies. The Malagasy names for these animals are: Tongona, Barimas, and Soamiera.
Contributors
Alexis Zenner (author), University of Wisconsin-Stevens Point.
Chris Yahnke (editor), University of Wisconsin Stevens Point.
Nancy Shefferly (editor), Animal Diversity Web Staff.
