What Animals Hibernate?

I know that a lot of animals disappear during the winter, but I wasn’t sure how many of them stay in the Rocky Mountains and hibernate versus how many of them simply go somewhere else.  So, I decided to do a little bit of research (which is super hard when you only have paws and no fingers to work a keyboard, but I managed to do it).

First it is good to know what exactly it means to hibernate.

Hibernation – a state of inactivity and lower metabolism in endotherms (animals that regulate their own body temperature).  Some signs of this are a lower body temperature, and a much slower than normal heart rate and breathing.

In other words, animals that truly hibernate all winter long are in a deep sleep like state for the entire winter.  They do not wake up and wander around unless they are disturbed by something, such as people or a flood.

Here are some of the animals that are true hibernators in the Rocky Mountains, meaning they do not wake up all winter:

Marmots – they hibernate for up to 200 days!  During this time their heart rate drops from around 180 to 30 beats per minute, their breathing slows from 60 to 1 or 2 breaths per minute, and their temperature drops to around 41 degrees.

Bees and wasps – many colonies have only one survivor all winter – the queen.  She finds a nice spot and hibernates all winter long till the spring when she can start a new colony.

Some frogs and toads – some frogs and toads will bury themselves in the mud at the bottom of lakes, or under logs or leaf litter to hibernate all winter long.  For example, the Leopard Frog hibernates underwater, and the American Toad hibernates under soil that it digs down into.

garter snakes many.jpg


Some Snakes -Garter Snakes – Some snakes in the Rocky Mountains do hibernate during winter.  For example, garter snakes will gather together in large dens with hundreds of snakes to hibernate during the winter.

Hedgehogs – stay asleep all winter long.

Little Brown Bat – bats hear rates slow dramatically, and they may only take one breath in an hour.

Some Ground Squirrells – they will go into their underground den and hibernate over winter.

The following animals are some of the light hibernators in the Rocky Mountains, which means that they sleep during the worst weather and may wake up to roam around during better weather:

bear sleepingBears – they are not true hibernators because they wake up sometimes.  They do not lower their body temperature close to freezing as most true hibernators do.  They keep is only a bit lower than normal both because they sometimes wake up (females wake up to give birth and then go back to sleep), and so that they can quickly wake up to protect themselves.

Skunks – the do not hibernate in the winter, but they do sleep a lot and stay in their den for weeks at a time.  They are active and come outside during periods of warmer weather.

raccoon snowRaccoons – similar to skunks they will sleep and spend bad weather in their dens.  But, when the weather improves they will come outside to look for food.

Some Chipmunks – Chipmunks sleep all winter, but they wake up every now and then in order to eat some food.  Unlike other animals they do not put on extra fat before hibernating.  Instead they gather food and store it in their den with them over winter.