An enornous Alaskan brown bear (grizzly) staring at the camera with killer looks

Are Bears Nocturnal? It Depends on Species and Gender


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Gabrielle Marks | Reviewed: 5/22/2025

Are Bears Nocturnal?

Answer at a Glance: North America is home to three species of bears: black, brown, and polar.  None of the three species is exclusively nocturnal. [1] The black bear is primarily nocturnal. The brown bears’ nocturnal habits depend on the gender of the animal.  The word nocturnal means nothing to the polar bear that lives in Arctic regions and experiences months of all daylight or darkness.


Dig Deeper


The Black Bear Is Primarily Nocturnal

cute black bear lounging in tree
“© 123RF.COM”

Generally speaking, the black bear is nocturnal, feeding from dusk until dawn.  But that doesn’t mean you won’t see a hungry bear in the daytime.  This is especially true in the months before winter hibernation when a black bear is fattening up for his long winter slumber.  During this time, a black bear may eat up to twenty hours daily, ingesting over 20,000 calories.  Eating twenty hours daily means the black bear is not nocturnal during this time of year. [2]

Brown Bears Are Nocturnal Depending On Gender

A brown bear with shaggy, brown fur is about to catch a salmon in its mouth at the top of Brooks Falls, Alaska. The fish is only a few inches away from its gaping jaws.
“© nickdale/123RF.COM”

Brown bears are generally reported as being diurnal, meaning that they forage for food during the day. Still, when researchers from the University of Victoria studied brown bears’ nocturnal and diurnal foraging behavior, they found that this fact was not entirely true.  The team observed the bears during the salmon spawning season and found that a mother brown bear with her cubs feeds during the day.  The opposite was true of the adult male brown bears.  They foraged equally in the daytime and the nighttime. Interestingly, the team noted that the capture rate was higher during the evening. [3]

Day and Night Are Irrelevant to Polar Bears

Two polar bear cubs playing together on the ice north of Svalbard
“© alexeyseafarer/123RF.COM”

Asking if a polar bear is nocturnal is a trick question.  Polar bears live in arctic regions that experience months of darkness and months of daylight, depending on the time of year.  If polar bears only foraged for food when it was dark out, they would not eat for months.  The same would be true if they only foraged for food when it was light out.  Like most animals, polar bears hunt for food when it is available.  For example, if the seals of the region are active at night, this is when the polar bears will hunt.  [4]

The sleeping habits of polar bears are similar to humans in that they sleep for 7-8 hours per day.  They also take short naps throughout the day, especially after a meal or during periods of inactivity. [5]       

References


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