Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The opposite is diurnality. The intermediate crepuscular schedule (twilight activity) is also common. Some species are active both in daytime and at night. Living at night can be seen as a form of niche differentiation, where a species' niche is partitioned not by resources but by time itself, for example temporal division of the ecological niche. It can also be viewed as a form of cry… (More on Nocturnality)