What primate is the only one known to hibernate for extended periods in the wild?

The primate known to hibernate for extended periods in the wild is the fat-tailed dwarf lemur.

This small lemur, Cheirogaleus medius, is endemic to Madagascar and survives the island’s pronounced dry season by entering prolonged dormancy. In the western part of its range, hibernation can last roughly six to eight months, making it an extraordinary exception among primates.

Before dormancy, the lemur stores fat in its tail and around its hindquarters. That reserve supplies energy while it remains sheltered, often inside a tree hole. Unlike many temperate hibernators, its body temperature can fluctuate with the surrounding temperature rather than staying steadily low.

A common mix-up is with mouse lemurs, which can enter torpor for several days, but are not the classic answer for extended hibernation. The fat-tailed dwarf lemur’s strategy is linked less to cold weather than to Madagascar’s seasonal shortage of food and water.