Silky sifaka

Propithecus candidus

The silky sifaka , or silky simpona, is a large lemur characterized by long, silky, white fur. It has a very restricted range in northeastern Madagascar, where it is known locally as the simpona. It is one of the rarest mammals on Earth, and is listed by the International Union for Conservation of Nature as one of the world's 25 most critically endangered primates. The silky sifaka is one of nine sifaka species , and one of four former subspecies of diademed sifaka . Studies in 2004 and 2007 compared external proportions, genetics, and cranio-dental anatomy supporting full species status, which has generally been accepted.

The silky sifaka has a variable social structure, and lives in groups of two to nine individuals. It spends most of its day feeding and resting, though it also devotes a considerable amount of time to social behaviors, such as playing and grooming, as well as traveling. Females occasionally take priority over males during feeding. Like other eastern sifakas, it consumes mainly leaves and seeds, but also fruit, flowers, and even soil on occasion. It is a seasonal breeder and only mates one day a year during the start of the rainy season. As with other sifaka species, non-maternal infant care is common. Group members of all ages and both sexes will often groom, play with, occasionally carry, and even nurse infants that are not their own. The silky sifaka vocalizes frequently despite its moderately sized vocal repertoire consisting of seven adult calls. Like all lemurs, it relies strongly on scent for communication. Males will frequently scent-mark on top of scent-marks made by other group members, particularly females. Males also gouge trees with their toothcomb prior to chest scent-marking. This chest marking results in males having brown-stained chests, the only visible trait that can be used to distinguish between adult males and adult females.

The species is only found within a few protected areas in the rainforests of northeastern Madagascar, with the majority of the remaining population in Marojejy National Park and Anjanaharibe-Sud Special Reserve. A few groups have also been found in the Makira Forest Protected Area, the Betaolana Corridor, and some unprotected forest fragments. The silky sifaka is hunted throughout its range as there is no local ''fady'' against eating this species. Habitat disturbance, such as slash-and-burn agriculture , illegal logging of precious woods and fuel-wood, also occurs within the protected areas where it is found.