Pygmy slow loris hibernates in winter

The pygmy slow loris truly hibernates, making it the first primate found outside Madagascar to do so, a new study says.

“Up until now there were only three species of primate known to hibernate: all lemurs in Madagascar,” says Thomas Ruf of the University of Veterinary Medicine Vienna. But in Vietnam, new measurements of wintertime body temperature for pygmy slow lorises (Nycticebus pygmaeus, one shown above) show bouts of chilly torpor lasting as long as 63 hours. A plunge in metabolic rate for more than 24 hours counts as hibernation, Ruf says.

There was talk about whether some unique conditions in Madagascar allowed the evolution of primate hibernation only there, Ruf says. But he and his colleagues dismiss that idea December 3 in Scientific Reports.