Underground hibernation in a primate

Hibernation in mammals is a remarkable state of heterothermy wherein metabolic rates are reduced, core body temperatures reach ambient levels, and key physiological functions are suspended. Typically, hibernation is observed in cold-adapted mammals, though it has also been documented in tropical species and even primates, such as the dwarf lemurs of Madagascar. Western fat-tailed dwarf lemurs are known to hibernate for seven months per year inside tree holes. Here, we report for the first time the observation that eastern dwarf lemurs also hibernate, though in self-made underground hibernacula. Hence, we show evidence that a clawless primate is able to bury itself below ground. Our findings that dwarf lemurs can hibernate underground in tropical forests draw unforeseen parallels to mammalian temperate hibernation. We expect that this work will illuminate fundamental information about the influence of temperature, resource limitation and use of insulated hibernacula on the evolution of hibernation.