Grades 3–5 · Organisms
How does hibernation help an animal use less energy?
Winter can make food hard for an animal to find. Some small mammals, including certain ground squirrels and bats, survive by hibernating. Before the difficult season, they build stores of energy. A sheltered place also helps protect them while they are much less active.
In the diagramHibernation lowers an animal’s energy useA small mammal can cycle between deep torpor and brief arousalSheltered ground squirrelDeep torporEnergy use: lowerBody temp: lowerStored energy still fuels the bodyHibernation is a regulated state, different from ordinary sleep.
During deep torpor, a hibernating mammal slows many body processes. Its heart beats more slowly, breathing slows and body temperature falls. These changes reduce the energy needed to keep the body going. The animal still uses energy, so hibernation does not make its need for fuel disappear.
Hibernation is different from an ordinary long sleep. It is a regulated change in how the body works. Many hibernators briefly become warmer and more active between torpor periods. Warming up takes energy too, before the animal may return to torpor.
The drawing follows a small-mammal pattern rather than every animal’s winter behavior. Species differ in how cold they become, how long torpor lasts and how they use stored food or fat. Lower energy use helps them last through a season when feeding may be difficult.
About this explanation
Starting knowledge: Know that animals need food energy and many have warm bodies.
Sources
- National Park Service — Hibernation: Nature’s Nap Time
- National Park Service — Arctic Ground Squirrel