The other night, while doing chimp counts during closing rounds, I climbed a ladder to look in the loft and found Negra building this magnificent nest.
There are a number of theories as to why chimpanzees build nests. Since most free-living chimpanzees build their nests high up in the trees at night, it’s possible that nest-building evolved to help protect chimpanzees from ground-dwelling predators or to avoid biting insects. There is also evidence to suggest that nests aid in thermoregulation. And these theories aren’t incompatible with the idea that chimpanzees also build nests because they are comfortable. Who doesn’t want a good night’s sleep?
At CSNW, we give out more than 70 clean blankets over the course of each day. If distributed evenly, that would be at least 10 per chimp – more than enough to make a comfortable nest, with some left over to use on top. But some of the Cle Elum Seven chimps, like Foxie, don’t really nest at all, while others, like Burrito, only use a few blankets. That leaves more for the master nest builders like Negra.
The chimps’ night nests are almost always made from blankets, but day nests are often made with other materials, such as bamboo, hay or straw, paper, cardboard, sand, fire hoses, and on at least one occasion, every single present given to the chimps for Christmas.