Why do some animals hibernate during winter?

Some animals hibernate during winter because they need to save energy when food is scarce and it's cold outside.

Hibernation is like going into a deep, cozy sleep for a long time. Just like you might snuggle under your blankets on a chilly night, some animals go even deeper, inside their homes, like caves or burrows, to stay warm and not use up all their energy.

During winter, the temperature drops, and there's less food around. Animals that hibernate have already eaten lots of food before winter started, so they store it in their bodies like a big snack stash. While they're sleeping, their hearts beat slower, and they don't need to move or eat as much, kind of like when you sleep through the whole day after eating too many cookies.

This way, they can wake up fresh and ready when spring comes!