Us humans are not the only ones that start to feel groggy and tired as winter comes and temperatures drop.

Throughout the state of Texas, many different types of animals have already entered or are about to enter a restful winter through either hibernation or brumation. Although both hibernation and brumation involve animals resting in winter, there is quite a difference between the two.


The Texas Parks and Wildlife Department shares that hibernation is a state between sleep and death that a warm-blooded animal enters. As temperatures drop outside, the animal begins to lower its heart rate to as little as four or five beats per minute and takes a breath every five minutes. Through this process, warm-blooded animals’ temperatures also drop to that of its surroundings.

Animals that hibernate during the winter tend to increase the amount of food that they eat in order to gain body fat. The TPWD explains that the animal’s energy consumption is so low during hibernation that it can survive off of its stored body fat.

Selina McSherry, the director of the San Angelo Nature Center, helped debunk the biggest misconception of hibernating and brumating animals never waking up. She says that the animals do wake up, however, when they go into this state and how long they remain there depends on the animal. The TPWD explains that animals like the Tricolored Bat can enter hibernation as early as September or October and are one of the last to emerge in the spring.

A few animals in Texas that hibernate include:

  • Ground Squirrel
  • Rock Squirrel
  • Squirrel
  • Big Brown Bat
  • Tricolored Bat
  • Eastern Red Bat
  • Deer Mouse
  • Hoary Bat
  • Ground Hog
  • Skunk


The University of Texas at Austin Biodiversity Center explains that brumation occurs in cold-blooded animals that cannot hibernate including snakes, turtles and fish. Animals that brumate experience a physiological change from October through April that is similar to hibernation. Texas temperatures very much affect brumating animals McSherry added.

“When it is a very cold day out there is very little movement on our indoor snakes and mammals outside,” said McSherry. “If it’s a nice, sunny 65- to 70-degree day there is movement throughout the facility. With warmer weather in the winter, it gives them a chance to be active.”

Similar to animals that hibernate, those that brumate eat more before winter. Unlike mammals, this increase in food helps build up glycogen or sugar in their blood instead of fat. The Biodiversity Center further explains that this sugar is used as energy in the muscles.

So while you are struggling to get out of bed this winter, remember, the animal kingdom is right there with you.