Among animals, birds spend considerable time preening their feathers. This is done to remove ectoparasites, keep them in good aerodynamic condition, and waterproof them. To do that, they use the preen oil secreted by the uropygial gland, the dust of down feathers, or other means such as dust-bathing or anting.
The pygmy hippo is reclusive and nocturnal. It is one of only two extant species in the family Hippopotamidae, the other being its much larger cousin the common hippopotamus (Hippopotamus amphibius). The pygmy hippopotamus displays many terrestrial adaptations, but like its larger cousin, it is semi-aquatic and relies on water to keep its skin moist and its body temperature cool.
Vervet monkeys serve as a nonhuman primate model for understanding genetic and social behaviors of humans. They have been noted for having human-like characteristics, such as hypertension, anxiety, and social and dependent alcohol use.
