How Do Mammals Survive the Winter?

Winter is coming to the Rocky Mountains…

Some people get ready for winter by chopping wood, cleaning out the gutters, checking the insulation on the house, and buying new winter coats for the family.  If it is going to be a really bad winter, then you may buy a new snow shovel or make sure the snowblower is working properly.

Not all mammals prepare for winter like this.  A moose does not walk down to the local store and buy a new snowblower and a mountain goat can’t wander into the local outdoor store and buy a new puffy winter jacket.

Instead, these mammals do what they have been doing their entire lives.  They either migrate, adapt, or hibernate.  Here are what some of the more common mammals do to survive winter.

dog sleeping

This is how I like to spend the winter!


Black Bears and Grizzly Bears choose to eat a lot of food in the fall time and then hibernate all winter long.  Bears will make their dens in a cave, a hollow tree, or even in the snow.  They do not go to the bathroom for the entire time that they are hibernating in their den during the winter, which can be as long as five or six months!

Although, they are not true hibernators because the females actually give birth while they are in their den during the winter.  The female will wake up long enough to give birth.  Then she will go back to sleep, leaving the babies awake as they drink the mother’s milk.

Chipmunks, Ground Squirrels, Raccoons, Marmots, and Skunks also hibernate during the winter.


In the Rocky Mountains many of the large herbivores migrate during the wintertime.  This includes Deer, Elk, Moose, and even Mountain Goats.  This does not mean that they travel hundreds of miles.  Instead, migration for these mammals means that they move lower on the mountains or even to the valley bottoms where it does not get as cold and there is more food available.


Some mammals survive winter by adapting, which means that they change something about their body or the kind of food they eat.  Mammals can’t go and buy a new coat for winter, but they have adapted and grow a thick winter coat.  A Mountain Goat and Elk grow thick winter coats to keep them warm during the coldest months of the year.

A Red Fox is an example of a mammal that changes the kind of food that it eats in order to survive the winter.  In the summer, a Red Fox eats fruit and insects.  But, in the winter it can not find those so it eats small rodents instead.