Where you sleep is important. If you’re like me, you like to sleep where you’re safe, comfortable, and with a full stomach. Northern pigtailed macaques (Macaca leonina), found in southeast Asia, have a similar checklist when choosing trees to sleep in: they have to balance avoiding predators, staying close to food, and keeping warm. 

Northern pigtail macaques sleep in large groups of up to 80 individuals. To avoid being spotted by predators at night, macaques and other canopy-dwelling primates will choose big, tall sleeping trees. And, to save energy looking for food, primates will sleep close to valuable fruit resources.  

What happens though, when the forest is fragmented, and has fewer good trees to sleep in? A recent study published in the International Journal of Primatology showed that macaques in Thailand's Sakaerat Biosphere Reserve are less likely to reuse sleeping trees in degraded habitat than in more pristine forest. But they are still systematic in their sleep site selection, choosing taller trees with more branches that are close to food resources. 

Northern pigtail macaques are listed as vulnerable on the IUCN Red List and their habitat continues to shrink. Understanding how these macaques respond to habitat changes is necessary for their conservation. The study authors suggest that macaques’ flexibility in choosing sleep sites is a good sign for the species’ resilience.