Lemurs normally live in trees, but researchers have discovered that at least two species hibernate underground.
Marina Blanco at the Duke Lemur Center in Durham, North Carolina, and her colleagues unearthed two species of eastern dwarf lemur (Cheirogaleus sibreei and C. crossleyi, pictured) in Tsinjoarivo, a high-altitude rainforest in central-eastern Madagascar.
By tagging 12 animals with radiotransmitters, the team found that the lemurs dig underground burrows in which they hibernate for several months between April and September. By contrast, the fat-tailed dwarf lemur (C. medius), the only other primate species known to hibernate annually, sleeps in holes in tree trunks. Being buried beneath an insulating layer of leaves and roots might help the eastern dwarf lemurs to maintain stable body temperatures amid large daily swings in air temperature, which often dip to 5 °C in the cold season.