The term for animals that mostly sleep during the day is "nocturnal." Nocturnal animals are adapted to be active at night and have evolved various physical adaptations, such as enhanced night vision, acute hearing, and heightened senses of smell to help them navigate and hunt in low-light environments. Examples of nocturnal animals include owls, bats, raccoons, and many species of insects. This adaptation allows them to avoid competition with diurnal animals that are active during the day, as well as to exploit nighttime ecological niches. Their behaviors also help them reduce predation risks and conserve energy.