What do animals do in winter when it gets cold?

When the first frost crackles across the grass and the wind starts biting at noses, the animal world faces one simple problem: it's cold, and the easy food is running out. So what's a creature to do? It turns out every animal has a different trick up its furry sleeve — and they all come down to three big strategies. Let's go meet them.
Strategy number one: leave. Just pack up and go somewhere warmer. This is called migration, and it's the animal version of booking a winter holiday. Birds are the famous ones — whole flocks rising up and flying south, sometimes thousands of miles, chasing the sun and the bugs that come with it.
