What Is A Hibernaculum? Snakes Know All About It


A bunch of snakes emerging in the spring from their hibernacula. Photo via Flickr.

Snakes hide in a hibernaculum when it is cold outside and snow is on the ground in the Rocky Mountains?  What is that exactly?

I have been talking a lot about what different plants and animals do in oder to survive winter.  All forms of life have some strategy to survive the cold winters of the Rocky Mountains.  Snakes are no exception, especially since they are cold-blooded they can’t remain active.  In order to survive, snakes in winter go into an inactive state and rest.  Many of them do this in a hibernaculum.


Photo via Flickr.

Snakes Enter A State Dormancy

The snakes in the Rocky Mountains go into a state of dormancy, but it is not the same as dormancy for mammals or bugs.  Snakes become inactive during the winter.  Similar to other reptiles though, they are not truly in a state of hibernation.

Instead of hibernation, snakes enter a state of brumation.  This is very similar to hibernation, but there are two differences between hibernation and brumation.  First, snakes need to wake up to drink water.  Second, they will sometimes wake up and go outside to warm up in the sun if it is a warm day.

snakes in winter, hibernacula

There may be hundreds of snakes in a hibernaculum over winter.  Look at this tangle of garter snakes! Photo via Flickr.

Some Snakes Enter A Hibernaculum Or A Den

Most snakes will go into a state of brumation in a den or a hibernaculum.  These are places that are below the ground, such as a crevice in the rocks, a cave, or other animals’ old burrows.  It is important that the spot be above freezing, and have some moisture (for drinking some water).

A hibernaculum is a spot that serves as a resting spot for animals during winter.

The hibernaculum could be a spot where tens to hundreds of snakes gather together.  They do this in order to keep each other warm.  Hibernaculums may even contain several different kinds of snakes, such as rattlesnakes, gopher snakes, or garter snakes.

The snakes stay in the hibernaculum all winter and then emerge in the spring and return to their usual areas.  Then come next winter, they make their way back to the same hibernaculum to stay warm and rest for another cold winter.

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