Nocturnal is defined as sleeping during the daytime and being active at night. For example, nocturnal animals hunt or graze and carry out other life activities during the night-time hours.
Beavers, hyenas, raccoons, gerbils and kangaroos are examples of nocturnal animals. Diurnal is the opposite of nocturnal and refers to being active during the day and sleeping at night. Humans are normally diurnal. Crepuscular refers to animals that are most active during the morning and evening twilight periods and sleep both during the day and at night. Bats, rabbits, rats and skunks are crepuscular. Some animals that are typically diurnal exhibit nocturnal behavior in certain places or at certain times of year as a means of protecting themselves or their young.