Each winter brown bears in North America spend an average of 5 months inside of dens in a low activity state known as hibernation. During this time, they experience drastic body changes. They also do not eat, drink, defecate (poop), or urinate (pee) during this time. It is a wonder that the bears can survive each winter in this state without performing these essential body functions! Average Stats for an Adult Male Brown Bear Fall - October

Going into Hibernation

Winter

During Hibernation

March - May

Coming out of Hibernation

Body Temperature

100°–101°F

about 88° degrees F

100°–101°F

Breathing Rate & Heart Rate

One way to measure energy used.

Normal

Very Slow

Normal

Heart Rate

40-50 beats per min

8-19 beats per min

40-50 beats per min

Weight

about 450 pounds

Not measured

about 250 pounds

Body Fat Percentage

Similar to DEXA scans—one way to measure how much fat the bear has stored.

30%

Not measured

15%

Use what you’ve learned from our investigations related to M’Kenna’s case and the data above to explain this phenomenon.

Make sure to include your claim and 2 pieces of evidence to support your claim.