资料题：This passage mainly discusses about（　）。

It's fun to walk in the woods in the winter.if you are quiet, you might see some animals.Many of them live there.If you don't see them, you might see their tracks in the snow.Animal tracks might take you to some tree.A tree is a very good place to look for animals.That's where some of them find food.Others make their homes there.You may see some birds at the top of the trees.Other animals, like squirrels and raccoons, live in holes part way up the trees.You can see a squirrel looking for food any time of the day.But raccoons come out only at night.In winter many rabbits live in holes in the ground.They do not make these holes.They move into ones that other animals no longer use.Rabbits sleep most of the day.They come out at night to eat and play.Rabbits eat many kinds of plants.They can even eat tree bark! Another animal you might see in the words is a red fox.The fox looks something like a dog.Foxes eat small animals.Sometimes they leave some food over.They hide it.Then they can go back and eat it at another time.There are animals that you won't see in the winter.One of these is a bear.These animals sleep all winter long.This way, they don't need much food.And they don't feel the cold.