During the colder months and when food is scarce, many animals react by slowing down their metabolism and entering some form of energy conserving state. By slowing down their metabolic rate, animals use less energy, need less food and can survive lower temperatures. Let’s look at hibernation, brumation and torpor: when animals sleep.
Most people think of bears when they think of hibernation but lots of other animals hibernate such as bats, bees, some rodents and groundhogs. Some animals hibernate for just the coldest few weeks of the year and some hibernate for months, depending on the climate and environment. Hibernation is more than just sleep. During hibernation, the animal’s body temperature drops significantly, their metabolism slows way down and the animal loses consciousness. In fact, waking a hibernating animal would cause its metabolism and temperature to rise, which could harm or even kill the animal. (So, leave hibernating animals be.)
Reptiles don’t hibernate but they do brumate. Brumation is different than hibernation as the animals who brumate can wake up on the random warm days to sun themselves and drink water to avoid dehydration, whereas a hibernating animal will not. Reptiles that brumate include snakes, turtles, lizards and alligators. Reptiles cannot control their metabolic reaction to the environment. Reptiles dig holes to brumate in as the temperature underground is more consistent than on the surface. In many cases, reptiles will share mud dens with other reptiles (even different species) to conserve and share warmth.
Torpor is different from hibernation or brumation because it can be a very short duration, such as one night or can be for an extended period, depending on the needs of the animal. Torpor is a period of decreased physical activity an animal intentionally enters to conserve metabolic energy. Torpor also helps the animal conserve energy but can happen any time of year, not just when it’s colder out. Some common animals that enter the state of torpor are many types of birds, opossums, some types of bats, skunks and some types of squirrels. Torpor allows an animal to conserve energy when food sources are scarce, like at nighttime or for a longer period like the colder months.
Hibernation, brumation and torpor all describe different ways animals sleep or conserve metabolic energy, whether it’s for a season or for a night. How deeply the animal sleeps and whether it can safely wake during the session varies depending on whether they hibernate, brumate or go into torpor. No matter what form of “sleep” the animal is in, it’s best to let sleeping animals lie and keep your distance if you happen upon one during one of these states.