The discovery of eastern dwarf lemurs of Madagascar hibernating in self-built underground shelters is reported in Scientific Reports this week. This finding uncovers details about the hibernation habits of these creatures, which had been poorly understood.

The dwarf lemurs of Madagascar are the only primates known to be obligatory hibernators. Fat-tailed lemurs in the western forests of Madagascar hibernate for seven months in tree holes, but there has been limited evidence about how their eastern relatives behave. Now, Marina Blanco and colleagues show that the eastern lemurs chose to hibernate in well insulated burrows for between three to six months each year. They found dwarf lemurs buried under a spongy layer of secondary roots and root hairs, humus and leaf matter.

These burrows are better insulated than the tree holes used by western lemurs, and the authors suggest that this resting place is more suitable for the cooler temperatures in the high altitude eastern forest. Thus, the study demonstrates that a clawless primate is able to bury itself underground to escape the challenges of winter.