Red-bellied lemurs are medium-sized primates with a luxuriant chestnut brown coat. These lemurs are distinguished by patches of white skin below the eyes, giving rise to a "teardrop" effect, particularly conspicuous in the male. Males in this species have medium-long dense dorsal coat of intense chestnut brown color. Ventrally they are lighter and redder in hue, while their tail, muzzle and head are black. Dorsal area and tail of females resemble the male but the ventral fur is a contrasting white-cream colour. Facial markings are similar to the male, except that "tear drops" are less exaggerated and spiry thick cheek hairs of the male are absent.
Red-bellied lemurs are native to eastern Madagascar. They occur as far north as the Tsaratanana Massif, and thence southerly to the Manampatrana River. This species does not occur on the Masolala Peninsula at all. Red-bellied lemurs live in the rainforest that is characterized by dense evergreen vegetation, with a canopy of 25-35 metres (82-115 ft).
Red-bellied lemurs are social animals and live in groups ranging from two to ten individuals. Females are dominant over males and are responsible for leading the whole group during foraging. Females have feeding priority and chose their own mates. Red-bellied lemurs are cathemeral, being active both during the day and during the night. Their home range is around 25 to 35 acres (10 to 14 ha). Groups are typically cohesive as they move within their home range, foraging on over thirty species of plants. Another way of maintaining social cohesion withing the group is grooming. These lemurs also communicate vocally, use scent marks, touches, visual signals and play with each other.
Red-bellied lemurs are monogamous and create strong pair bonds. Births normally occur in October and November (early summer in this Southern Hemisphere habitat). Females give birth to a single infant per year. The gestation period lasts around 127 days. Young are born altricial and weigh 60-70 grams. Both parents take part in raising their offspring. The infant uses its prehensile instincts in order to attach to the mother and father alternately for the first 33 to 37 days of life. After this time the mother often refuses to carry the infant further letting the father take care of their baby for another nine weeks. Young are usually weaned at the age of 5 to 7 months.
The main threat to Red-bellied lemurs is the loss of their habitat due to slash-and-burn practices and illegal logging. These animals also suffer from hunting, especially in certain areas, such as Mantadia.
According to the IUCN Red List, the total population size of the Red-bellied lemur is unknown. However, there is an estimated population of the species within Ranomafana National Park consisting of 1,802 individuals. Currently, this species is classified as Vulnerable (VU) on the IUCN Red List and its numbers today are decreasing.
Due to their diet, Red-bellied lemurs are very important as seed dispersers withing their range.