In Animals
Animals that are not diurnal might be nocturnal (active at night) or crepuscular (active primarily during twilight, i.e., at dusk and dawn). Many animal species are diurnal, including many mammals (including humans), insects, reptiles and birds. In some animals, especially insects, external patterns of the environment control the activity (exogenous rhythms, as opposed to patterns inherent in the habitat). Diurnality is descriptive; it refers to an observed 24-hour pattern, as opposed to ~24-hour circadian rhythms which are self-sustaining within the organism.
Some mainly nocturnal or crepuscular animals have been domesticated as pets and have changed into diurnal animals to coincide with the cycle of human life. Examples are pet dogs and cats, which are derived from the wolf and the wild cat, respectively. However, these animals may exhibit their species' original behavior when they are born feral. Other animals have been forced from their normal cycle to an alternate one as a means of avoiding predators, such as beavers becoming nocturnal creatures after extended predation by mankind.
Read more about this topic: Diurnality
Famous quotes containing the word animals:
“Error has made animals into men; is truth in a position to make men into animals again?”
—Friedrich Nietzsche (1844–1900)
“Russian forests crash down under the axe, billions of trees are dying, the habitations of animals and birds are layed waste, rivers grow shallow and dry up, marvelous landscapes are disappearing forever.... Man is endowed with creativity in order to multiply that which has been given him; he has not created, but destroyed. There are fewer and fewer forests, rivers are drying up, wildlife has become extinct, the climate is ruined, and the earth is becoming ever poorer and uglier.”
—Anton Pavlovich Chekhov (1860–1904)