When you’re a wild animal, surviving harsh winter weather and food shortages can be a challenge. Animals have adapted in many areas, including wintering. While often thought to be a long sleep, hibernation is in fact quite different, with the animals lowering their metabolism, temperature, heart rate and respiration to reduce their need for food.
While bears are probably the first animal that comes to mind when you think of hibernation, they don’t actually hibernate, at least not in the truest sense of the word. Bears go into torpor, which is similar to hibernation, but different. When in torpor, bears reduce both their heart and breathing rates, and their temperature drops, but to a lesser extent than animals that hibernate. When bears are in torpor they can get up more easily, but they can also sleep for days without getting up, eating, drinking or going to the toilet.
9. Garter Snakes
While many animals hibernate alone, the hibernation of the garter snakes is a group activity. Hundreds or perhaps thousands of snakes congregate in a burrow to hibernate. The close proximity helps them to keep warm, which is important for the cold-blooded animals.
8. Box Turtles
Many turtles hibernate, but this varies by species and location. Box turtles can hibernate for three to five months of the year. They dig an underground burrow for themselves, lower their heart rate to 5-10 beats per minute and completely stop breathing. But, they don’t go without oxygen, because they absorb it through their skin.
Snails may not be the first animal you think of when it comes to hibernation, but some do. When they hibernate, snails retreat into their shells and seal the entrance with mucus to retain moisture and keep them from drying out. Not only do they do this in cold weather, they also protect themselves against warm weather, also known as aestivation, the counterpart of hibernation namely a so-called ‘summer sleep’.
Wouldn’t it be nice to sleep through the winter? Well, marmots can, or at least hibernate, sometimes for eight months. During hibernation, marmots can lower their heart rate to 3-4 beats per minute and breathe 2-3 times per minute.
There’s a reason you don’t hear much about birds that hibernate, and that’s because most don’t. The poorwill is the only one, and that is because the insect food is not available in winter. Instead of migrating, the birds cuddle up in a hollow log and wait for winter by lowering their metabolism and overwintering.
Bats go into a state of torpor, a reduced hibernation, during the night when temperatures drop or food becomes scarce. Some species go a step further and hibernate, but in general they are those that live in areas where there are fewer insects during the winter months. When in torpor or hibernation, bats cling to ceilings or cave walls and can reduce their heart rate to 10 beats per minute.
3. Spiny Tiles
Hedgehogs can hibernate for weeks or months, depending on how cold the winter gets. During hibernation, hedgehogs can drop their heart rate by up to 90%, but can wake up momentarily if it gets too cold. The increased heart rate when they wake up warms them up slightly before falling back asleep.
Not all bees hibernate, but for the bumblebees hibernation is a part of life, at least for the queen. All the males and worker bees die when the temperature drops, leaving the queen looking for a suitable place to await the winter. When the temperature rises, the queen emerges, builds a nest and lays a whole new colony.
1. Forest frog
Forest frogs go one step further than most of the animals on this list when it comes to hibernation, because they stop breathing and their hearts stop beating completely. In fact, they cool so much that ice crystals form in their blood. They sleep in logs, burrows or leaf mounds to stay there during the winter until the summer returns to the land so that they can warm up and start breathing again.