Crepuscular

What "crepuscular" means

A crepuscular animal is most active during twilight: the dim periods around dawn and dusk. The word comes from the Latin crepusculum, meaning "twilight."

Crepuscular sits between the other main activity patterns:

• Diurnal: active during the day
• Crepuscular: most active at dawn and dusk
• Nocturnal: active at night

There are two more specific terms. Matutinal animals are active mainly at dawn, and vespertine animals mainly at dusk. The lines aren't absolute: crepuscular animals may also be active on a bright moonlit night or a dull, overcast day. And many animals people call "nocturnal," such as rabbits, are often better described as crepuscular.

Why some animals are active at twilight

Twilight offers a useful middle ground:

• Safety from predators. Many predators hunt mainly at night, and others hunt at midday and see best in full sun. Twilight can fall between them.
• Beating the heat. In hot climates, dawn and dusk are cool enough to stay active while there's still some light.
• Following prey. Some predators time their hunting to when their prey is out. The bobcat is mostly active during twilight, often from a few hours before sunset until about midnight and again from before dawn until a few hours after sunrise.

Crepuscular animals you can see at the zoo

Familiar crepuscular animals include:

• White-tailed deer, which are most active at dawn and dusk and rest at intervals through the day and night.
• Bobcats, which are mostly active during twilight.
• Chinchillas, crepuscular rodents native to the Andes.
• Red pandas, which are active at twilight and at night.
• Rabbits, along with many other small mammals such as hamsters and some squirrels.

Some birds are crepuscular too, including the common nighthawk, the barn owl and the American woodcock.

What it means for your zoo visit

Most zoos open after sunrise and close before dark, so you'll catch only the edges of a crepuscular animal's active time. To improve your odds:

• Be there at opening. The first hour is the closest you'll get to dawn activity.
• Stay late. Many animals start stirring again in the late afternoon, especially in summer.
• Watch for after-hours events. Some zoos host evening or seasonal night events, which can be a great time to see twilight-active species.
• Visit on cool or cloudy days, when crepuscular animals may stay active longer.

Find a zoo near you in our zoo directory.