From the common squirrel to the gray garden dormouse. Exploring the deep sleepers of the animal kingdom

Both humans and animals feel the impact of winter on their daily lives. While humans can bundle up in blankets with food from the grocery store, animals must find a way to survive the harsh winter months, often with limited access to food. Most of them hibernate, meaning they remain largely unaware during the worst parts of winter. By the time they awaken, the weather is warmer, and nature is beginning to revive.

Nature, in its wisdom, devised what we now call hibernation. It's not exactly what you might think. Hibernation is primarily about conserving energy. Many animals burrow into dens to avoid freezing. Their heart rate slows to the bare minimum required to circulate blood efficiently, using as little energy as possible. This state is often likened to clinical death, where the heart's rhythm is so faint that monitoring machines often fail to detect it.

Hibernation is not uniform among animals. Many animals enter a sort of light winter sleep, during which their body temperature and breathing rate drop significantly. This sleep could be likened to the rest humans take after a long and tiring day. They maintain this sleep pattern for several months, waking only to eat and drink. Bears are a prime example, occasionally leaving their dens during winter.

Various animals hibernate to different extents. One example is the common squirrel, which hibernates for about two months. Interestingly, squirrels are not solitary during this period, often opting to hibernate in pairs or small groups. The gray toad or grass frog must endure much longer and harsher conditions, which leads these amphibians to hibernate for about five months.

As for hibernation record holders, three species hibernate the most. The groundhog can slumber for up to seven months, from October until April. Before hibernating, it gains weight and wakes up approximately every three weeks.

Next is the spotted suslik, which starts dozing in August and does not awaken until April. However, their daily activity only lasts for 5-6 hours, with the remainder spent sleeping. The final champion of hibernation in our list is the gray garden dormouse, a small rodent that hibernates at the first signs of frost, typically waking up only in May or June. Now that's what I call a deep sleeper!