What is Torpor? What Animals Do It During Winter?


Photo via Flickr.

Torpor is a deep sleep like state that some animals go into at night during the cold winters of the Rocky Mountains.  Do you know how torpor is different than hibernation?

It is winter time and I find it hard to believe that any animals can survive the cold nights.  Animals choose different strategies to survive winter, such as migrating, adapting, or going into a state of torpor.  Here is some general information about torpor, what animals go into it at night, and how it differs from hibernation.

What is Torpor?

This is one of the winter survival strategies that animals choose in order to survive the long, cold winters of the Rocky Mountains.

It is a short term reduction in body temperature and metabolism.  This also means that the animal slows down its breathing to the point that it may even appear the animal is dead.  In fact, a hummingbird in torpor may even be hanging upside down on a branch.  It is generally done on a daily or nightly basis so that the animal can survive the night.


Small animals, like this raccoon go into torpor at night. Photo via Flickr.

What Animals Go Into Torpor?

It is fairly common, especially for small mammals who have a greater challenge with maintaining their high body temperatures during cold nights.  Smaller animals have a high surface to volume ration, which means they lose body heat faster than larger animals.

Some of the animals that do this include: chipmunks, raccoons, skunks, squirrels, and some birds such as hummingbirds and chickadees.

Why Do Animals Go Into Torpor?

In cold temperatures it takes a lot of energy for animals to maintain a high body temperature.  During the winter time there is not a lot of food available, so it is hard for animals to get energy.  Thus, it is a way for those animals to save their limited energy reserves during very cold temperatures.

How Is Torpor Different Than Hibernation?

They are different in how long the reduced body temperature and metabolism last for.  Torpor is short-term (usually done for one night) and hibernation is long-term (done for several months).  Read more about hibernation here.