Orangutans nap to make up for lost sleep https://www.mpg.de/24896387/0618-ornr-orangutans-nap-to-make-up-for-lost-sleep-987453-x
New study reveals that wild orangutans recover from sleep loss with daytime naps
Bartalotta / Suaq Cissy, a Sumatran orangutan mother is taking a nap in her day nest