Crepuscular [kri-puhs-kyuh-ler] refers to animals that are primarily active during dawn and dusk. The term is derived from the Latin word ‘crepusculum,’ meaning ‘twilight.’ Crepuscular animals may also be active on a bright moonlit night. Some species are active only in the dawn (matutinal) or only in the dusk (vespertine). Many animals that are casually described as nocturnal are in fact crepuscular, including most cats. Others crepuscular species include include dogs, rabbits, pigs, rats, deer, skunks, and wombats. Many moths, beetles, flies, and other insects are crepuscular as well.
The patterns of activity are thought to be an antipredator adaptation. Many predators forage most intensely at night, while others are active at mid-day and see best in full sun. Thus the crepuscular habit may reduce predation. Some species have different habits in the absence of predators. For example, the Short-eared Owl is crepuscular on those of the Galápagos Islands that have buzzard species, but diurnal on those without. Additionally, in hot areas, it may be a way of avoiding thermal stress while capitalizing on available light.
The Daily Omnivore 
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