Reindeer are large deer that live in the cold northern regions of Europe, Asia, and North America. Unlike most deer species, both male and female reindeer grow antlers, which they shed and regrow each year. These animals are remarkably adapted to frigid climates: their thick fur coats have hollow hairs that trap air for insulation, and their wide hooves work like snowshoes to keep them from sinking into deep snow.

In North America, reindeer are called caribou when they're wild, though they are the same species. For thousands of years, people in places like Scandinavia, Siberia, and northern Canada have herded domesticated reindeer for their meat, milk, and hides, and as animals to pull sleds across snowy terrain. Wild caribou migrate incredible distances each year, sometimes traveling over 3,000 miles in search of food.

These animals survive harsh Arctic winters by eating lichens (organisms made of fungi and algae that grow on rocks and trees), along with grasses and small plants. Their thick neck muscles and strong sense of smell help them dig through snow to find food buried underneath.

You probably know reindeer best from Christmas stories, where Santa's sleigh is supposedly pulled by flying reindeer. While real reindeer can't fly, they're impressive enough on the ground.