AskDefine | Define crepuscular

Dictionary Definition

crepuscular adj : like twilight; dim; "the evening's crepuscular charm"

User Contributed Dictionary



From creper, "dark, dusky".


  • italbrac RP /krɪˈpʌskjələ/ or /krɛˈpʌskjʊlə/
  • italbrac US /krəˈpʌskjəlɚ/
  • ,


  1. Of, or related to twilight; dim
  2. active at or around dusk, dawn or twilight


of, or related to twilight: active at or around dusk, dawn or twilight:

Extensive Definition

For the atmospheric optical effect, see crepuscular rays.
Crepuscular is a term used to describe animals that are primarily active during twilight, hence at dawn and at dusk. The word is derived from the Latin word crepusculum, meaning "twilight". Crepuscular is thus in contrast with diurnal and nocturnal behavior. Crepuscular animals may also be active on a bright moonlit night. Many animals that are casually described as nocturnal are in fact crepuscular. Within the definition of crepuscular are the terms matutinal (or "matinal") and vespertine, denoting species active in the dawn and dusk respectively.
The patterns of activity are thought to represent a response to selection from predators. 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. Additionally, in hot areas, it may be a way of avoiding thermal stress while capitalizing on available light.
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.
Many moths, beetles, flies, and other insects are crepuscular as well.


crepuscular in German: Temporale Spezialisten
crepuscular in Persian: پگاه‌رو
crepuscular in Indonesian: Krepuskular
crepuscular in Icelandic: Rökkurdýr
crepuscular in Dutch: Schemeractief
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