#7 – Celebes Crested Macaque
Celebes Crested Macaques can be called swingers – both literally and figuratively. They live in the forested areas of northeast Sulawesi in addition to other neighboring islands in Indonesia
Males and females are free to mate with various partners. Swingers, get it? When it’s hot, female’s buttocks turn red to swell up to a size that’s noticeably disproportionate with the rest of its body. Creepy.