Hibernation & Torpor

Posted on November 20, 2017 by Leslie Ann Daniels

Thanks to Oak Meadow’s K-4 teacher, Sarah Antel, for this wonderful addition to our blog. 

As autumn finally settles in Vermont, I always notice mental and physical changes in myself. I am found in the kitchen making soups, stews, and bread, I pick up the handwork I abandoned last spring with renewed interest, and I often feel fatigued as the early evening darkness falls; a purring cat on my lap helps this state of calm occur more easily.
Even though it may seem many plants have died outside with a morning frost, I see this season as a time of rest and ultimately, renewal. A good rest often helps one to rise refreshed and ready to work. Winter is nature’s time to rest. The trees have dropped their leaves and stored the food they made in their roots, plants of all kinds have scattered their seeds, and many animals are nesting in warm places, preparing for the winter respite.
As winter draws near, people often remark that animals are getting ready to hibernate. This statement is only accurate for a handful of animals here in the Northeast. If animals do not migrate or stay active in the winter months, many enter a state of torpor, or light hibernation during the colder weather; most do not hibernate.

Photo Credit: Morgan Wiebke

An animal that is considered a “true hibernator” stores fat reserves, their breathing slows to as little as one breath a minute, their heart rate often registers at four beats per minute, and their body temperature lowers close to the temperature of the surrounding air. Often, these creatures will not awaken, even if they are handled. The only animals that are true hibernators in the North East are bats, groundhogs, and jumping mice. Many other animals, including bears, go into torpor. These animals’ bodies stay very close to their normal temperatures. Additionally, their breathing and heart rates do not slow. They are easily awakened and will often be found foraging for food during a warm spell. Reptiles, like snakes, can be found in dens in a state of torpor, but they will sometimes be seen warming themselves when the sun’s rays beckon. Amphibians bury themselves in the soil, often at the bottom of a pond. But these creatures also can awaken during the winter as some people have spied them moving about below ice.
Although the winter season may seem like a silent time for nature, there is still an abundance of activity and life beneath the blanket of snow. If you live in a place where snow falls in the winter, you may want to set up a subnivean zone board so you can observe some activity that happens below the snow. Once there is some snow on the ground, lay a wide piece of wood like a large piece of plywood, over some seeds you sprinkle on top of the snow. In a few days, gently lift the board to peek underneath. Many of the seeds may be gone and you may see a network of tunnels under the board. The subnivean zone is the area in and underneath the snowpack where some small mammals like mice, voles, and shrews live out the winter and forage for food. Staying in the subnivean zone helps to protect them from predators and insulates them from the cold winter air. Sprinkle more seeds throughout the winter so these creatures can have a place to find food and you can make scientific observations all winter-long.
This post was written by Oak Meadow’s K-4 teacher, Sarah Antel. 

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