The Red-ruffed Lemur is native to rainforest in a small area of north-eastern Madagascar. They live in monogamous pairs or small female-led groups.
Grooming is an important activity, both self and mutual grooming, and they have a grooming claw and "tooth comb" for the purpose.
It is one of only two primates to build a nest in trees, the other being its close relative the Black and White Ruffed Lemur. Both ruffed lemurs are the largest of the lemurs.
Although its range does not overlap with the Black and White, it is said that the two species can understand the alarms and other communicating calls of each other.
Natural predators include boas and the fossa, which is a nocturnal hunter when the diurnal lemurs are sleeping.
The Red-ruffed Lemur is critically endangered, having suffered population loss from hunting and from habitat destruction for logging, mining and agriculture.