Chicago's Best Bat Removal

Do Bats Migrate? Where Do Bats Live in the Winter?

Winter brings about many changes for people. We tend to stay inside to avoid cold weather or bundle up and spend the day in the snow. We have developed methods to cope with the cold in North America. Nature did not leave bats out of the equation when giving them the question of whether to migrate or hibernate. Bats have such a wide variety of species and developed the ability to do both. Their bodies are highly adaptable for migration and hibernation, and even some members of a given bat species do the opposite of the majority.

What Are Migration and Hibernation?

Migration means the bats travel from one location to another in preference for better weather conditions, mating habits, and food sources. Hibernation means shutting down the body functions to use less energy than if the bats were awake and flying. There are as many as 1,300 species of bats across the globe. There are such vast differences even within the same species. Most bats that hunt in one area migrate a relatively short distance to get to winter hibernation sites.

Which Do Bats Do?

Some bats have been known to hibernate for up to 9 months with only a couple of grams of stored fat. Others migrate long distances across the continent. Several smaller colonies of similar bats find the same handful of caves to hibernate further north than in their southern summer active season. They hibernate in those particular caves because the atmosphere and temperature are controlled and consistent year-round. Banding together, they create hibernaculas with hundreds of thousands of bats.

Hibernacula

Other hibernacula locations are really open to what the species of bat needs. Many with extremely specific temperature needs are becoming endangered because their hibernation locations are being disturbed or destroyed. Caves and old mine shafts can create the right mix of air movement, consistent temperatures, and reliable humidity. Bats only arouse during hibernation to drink and urinate.

With the right combination of factors, water condensates on the walls and their fur. Several species arouse multiple times every 12-19 days, but if the weather gets colder, they can go as long as 80 days without rousing if they need to.

Active Winter Bats

Bats' bodies are covered in fur. Their wings are skin-like membranes between their forelimbs and their body. The design for their wings is focused on dexterity while flying to hunt. They are not specifically designed for speed or distance, which means hibernation can take priority for many of them. Some bats have thicker fur and other methods of staying warm. One species uses its lengthened and wide tail as a blanket of sorts to stay warm. Others do not require such strict control of temperature and, so long as they have food, they can keep warm on their own in trees. Those who are more consistently active and only use torpor as a method of survival migrate to warmer climates like birds.

Both Functions Are Common

Generally, a bat can both migrate and hibernate even if they only do one of those during cold months. The same species that migrates across the continent can choose to hibernate instead. There are benefits to changing the existing behavior of the majority. Preliminary research suggests that some males hibernate while the rest of the species migrates. The theory is they will have first access to returning females for mating in early spring. Bats can enter torpor during cold spells, even if they were active during the warmer winter days before.

More than Cave Exploration

Caves are just one aspect of hibernation, but many bats utilize spaces all over. The eaves of a house can be a temporary place for them to rest during migration. Trees with good coverage overhead can work too. Attics can become maternity colony roosts if the right conditions are met.

Many bat hibernation sites are at risk. Changes can cause the loss of bat populations. Some species' layover caves can be just as important in their survival. Having dedicated locations to be safe in between winter and summer roosts can make a difference in population.

Most states have laws against dealing with bats in an inhumane way. They are vital to the ecosystem and thus many are protected. Even the ones who are not specifically listed at your local wildlife department are still bats and need to be handled with care.