The Silky sifakas are unique, easily recognizable lemurs with a creamy white coat, due to which these animals are otherwise called 'angels of the forest’. Their coat is long, soft and silky, colored in white and tinged with silver on their back, legs and the head top. These lemurs exhibit furless, black faces as well as deep orange eyes. The lower back and the base of their tail are often darker and discolored. Mature males of this species are distinguished by the characteristic large, brown colored area on their chests. This is a result of their scent-marking habit, during which they use the special gland on the chest. Some individuals display pink areas on different parts of their body because of lacking skin pigment. The life expectancy of the population in the wild is currently unknown. Additionally, these animals cannot live in captivity, which doesn't allow to determine their lifespan. However, the closely related Verreaux's sifakas are known to live more than 23 years.
The Silky sifakas are endemic to Madagascar. The natural range of these animals covers a tiny area of the island, extending from Marojejy southwards to Makira and the Antainambalana River. However, the limits of their range are unknown. These lemurs are generally found in montane and mid-altitude rainforest habitat. Overall, they occur at high elevations, preferring a wide variety of habitats such as sclerophyllous forest or low ericoid bush, found at the highest elevations of their range.
The Silky sifakas live in a female-dominated society, forming groups of 2 - 9 individuals, consisting of one or more breeding pair, as well as smaller family units of an adult male and female with their young. Each group has its own territory, which can be up to 44 hectares in size. These groups are known to take daily trips of about 700 meters within their territory. The Silky sifakas are diurnal animals. The most of their active time is generally spent resting and looking for food. More precisely, 45% of the day is spent resting and up to 22% - foraging. Other important activities include grooming and playing as well as very short periods of moving. Usually, females tend to spend their time resting as much as possible, while males display more sociable behavior, moving around to participate in various activities. The Silky sifakas rest by bending their knees to hold them close to the abdomen and clinging to a vertical tree trunk.
The reproductive system of this species is insufficiently explored. However, it is believed to largely depend on the social structure of a given community, since the Silky sifakas live in various units such as multi-male and/or multi-female groups, mixed groups or all-male groups. Hence, different groups of these lemurs may have either polygynous (each male has numerous mates) or monogamous (each individual has only one mate) reproductive systems. They are likely to have a very short mating period of a few days, occurring between November and January. Most births take place in June-July. Females usually give birth at intervals of 1 - 2 years. Gestation period lasts for 6 months, yielding a single infant, which will cling to the belly of its mother. Then, by 4 weeks old, the baby begins riding on the back of its mother. It will stay close to its mother, sleeping with her until becoming mature. Meanwhile, community members typically help the female to rear its offspring by carrying, nursing, grooming and playing with the infant.
One of the biggest threats to the population of these animals is habitat disturbance and destruction. Another serious concern is hunting, compounded by the absence of any local taboo (or fady) against hunting and consuming Silky sifakas. Moreover, these lemurs are commonly hunted even within the protected areas of Marojejy National Park and the Anjanaharibe-Sud Special Reserve.
According to the IUCN Red List, the total population of Silky sifakas is less than 250 mature individuals. Currently, this species is classified as Critically Endangered (CR) and its numbers continue to decrease.
The ecological niche of this species is unclear. However, the silky sifakas probably act as important seed dispersers of their range due to their folivorous diet. Additionally, they are hunted and consumed by humans and fossas.