Most primates are not known for their hibernation habits—except for the western fat-tailed lemur that hibernates for seven months in a tree hole. But in 2013, scientists discovered two new lemurs in Madagascar that did hibernate— Crossley’s dwarf lemur and the Sibree’s dwarf lemur. Unlike more hibernators that lower their body temperatures and hide in special hidden spots in the cold winter, the western fat-tailed lemurs actually hibernate from the cold and the heat, with temperatures that can reach 85°F (29.4°C) over a long, dry season—when food and water are in short supply.

But the two new lemurs live in the high-altitude forests, where it does go below freezing. The scientists found that although the animals burrow underground and breathe once every several minutes, their temperature does not drop, remaining constant. This may indicate that primates as hibernators are more prevalent than we think.