Why Do Some Animals Hibernate in the Winter?

hedgehog hibernating in nest of leaves

At this point in winter, Alabama’s forests, woodlands, and wetlands are much quieter than usual. Many creatures that commonly roam these habitats in the spring, summer, and late fall have migrated to warmer climates.

However, there is still plenty of winter wildlife nearby. During the day, herds of white-tail deer and a few other species are out and about, but most wildlife hides away, keeping warm in burrows, caves, huddles, and nests. 

Whether cuddled up in packs or curled up on their own, the many animals that stay out of sight all winter are either in torpor—a low-activity state similar to hibernation yet not completely immobilizing—or in hibernation. This raises the question: “Why do some animals hibernate?”

Why Do Some Animals Hibernate?

Animals don’t “know” to hibernate as far as being taught. Instead, in the autumn, a chemical compound called a Hibernation Induction Trigger (HIT) is released into an animal’s bloodstream, and their instinctual response is to get ready to hibernate.

If you didn’t know, hibernation is not just a long winter’s nap. Technically, a hibernating animal isn’t “sleeping,” nor is it in a normal state of being awake. When animals are simply asleep, the activity rate within their brains and some involuntary physiologic processes—metabolism, heartbeat, and respiration—slow down, and their body temperature drops. 

Animals in hibernation experience these same changes but at a much more drastic rate, and again, they’re not always sleeping. Sometimes, hibernating animals get some slow-wave sleep. Yet, even if they’re somewhat awake, they always look like they’re sleeping in constant dormancy, where all voluntary bodily movement and most conscious sensory perception shuts down.

Energy Conservation

Since hibernation is not one long slumber, it does not generate energy through restfulness. Instead, hibernation eliminates some of the animal’s energy needs and helps some species of warm-blooded animals conserve energy. To understand how this works, you need to know about endotherms and ectotherms:

  • Cold-blooded, AKA ectothermic animals’ (“ectotherms”) internal body temperatures rely on the temperature of the environment they are in. To stay warm, they must stay in warm climates.
  • Warm-blooded, AKA endothermic creatures (“endotherms”) generate heat within their bodies and, therefore, can stay warm internally, less reliant on environment temperature than ectotherms.

Endothermic animals have a higher chance of survival during the winter than cold-blooded creatures, who often have to migrate somewhere warmer for the season. 

Inadequate Energy Supply 

Energy conservation is such an essential benefit of hibernation because endotherms need fuel (nutrients from food) to produce energy to generate body heat and other functions. However, the winter’s frigid temperatures and few hours of direct sunlight can impact the whole food chain and cause an inadequate food supply. 

With scarce sunlight, plants cannot sprout, grow, or reach maturity to produce food sources like fruits, seeds, nuts, vegetables, and berries. When all of the plant life in a habitat dies off and pauses all growth for the season, herbivorous animals—that’s any creature with a plant-exclusive diet, including most pollinating insects and small mammals—either migrate to a warmer area or hibernate somewhere safe. 

Many larger animals higher on the food chain, even carnivorous or omnivorous predators, starve into hibernation. For the winter, smaller prey animals are off the carnivore’s menu wherever they’re safely hibernating (or hiding in torpor). However, some large carnivores, like mountain lions, have no trouble finding food and stay active all winter. 

Leaving Wildlife Where it Belongs

When wild creatures remain in their natural habitats, fascinating phenomena like hibernation can run their course. 

However, if wild animals venture into areas of human development in their search for safe, warm hibernation, they, people, and pets can be in danger. Call an animal or pest control professional immediately if you discover wild creatures hiding on your property. We can handle the situation and keep your family safe.

At Vulcan Termite and Pest Control, we have proudly served families in Alabama since 1965, and we would love to help yours, too! Call us at 205-663-4200 or contact us online today to learn more about our affordable, effective pest control solutions.

Thanks for reading! To learn more about the pests and other creatures found here in Alabama, check out our pest blog.