The diademed sifaka (Propithecus diadema), is a critically endangered species of sifaka, one of the lemurs endemic to certain rainforests in eastern Madagascar. Along with the Indri, this species is one of the two largest living lemurs, with an average weight of 6.5 kg and a total adult length of approximately 105 cm, half of which is its tail. The species occurs from 200 to 800 m elevation throughout much of the eastern Madagascar lowland forests, and from 800 to 1,550 m in portions of the montane Madagascar subhumid forests. As of 2002, population estimates for the species range between 6,000 and 10,000 individuals.