Ask a Naturalist: Hibernation vs. brumation vs. estivation

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As the weather turns cold, many animals have gone into hibernation to get through the winter.

But hibernation isn't the only type of dormancy an animal can experience, and winter isn't the only time of year animals might go to sleep or reduce their activity to survive.

The environment that an animal lives in affects their dormancy behavior greatly.

Animals might go through hibernation, brumation or estivation (aestivation). These terms can be confusing because there are similarities between them all, but there are distinct details that make each process different.

Most people are familiar with the term hibernation, a state of dormancy that endotherms, or warm-blooded animals, do.

The body temperature, heart rate, breathing rate and metabolic rate of the animal slows down during the winter months. This occurs so the animal can conserve energy and survive during the cold months.

Animals can hibernate for several days, weeks or months, depending on the temperature in the area and the individual animal's condition.

Rodents such as the chipmunk (on exhibition in Creature Cavern) and ground squirrel go through true hibernation.

Brumation is known as the hibernation for cold-blooded animals. Ectotherms rely on their environment to regulate their body temperature.

Cold temperatures cause reptiles and amphibians to hide underground, in rock crevices and in burrows to stay warm and safe. Their activity, body temperature, heart rate and respiratory rate drops like in hibernation.

Cold-blooded animals will move on warmer winter days and find water, unlike hibernators who are in a deep sleep and do not move at all.

Estivation is when animals are dormant because weather conditions are very hot and dry. Their breathing rate, heart rate and metabolic rate decrease to conserve energy under these harsh conditions.

These animals will find a spot to stay cool and shaded. Many reptiles and amphibians estivate and some mollusks, insects, fish and mammals will estivate as well.

Whether it is hibernation, brumation, estivation or a combination of these processes, animals have an amazing ability to adapt and survive in their different environments.

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