Reindeer, as they are known in Europe and Asia, and caribou in the Americas

They are the only deer in which male and females both have antlers—though these are larger in the males than females and only some females have them.
They live in huge herds as both resident and migratory populations.
As summer approaches, many reindeer herds of tens or even hundreds of thousands head north along well trodden annual routes. Some populations migrate the furthest of any terrestrial mammal, traveling up to 5,000 km a year.
During migration, herds of cows (females) leave several weeks before the males, who follow with yearling calves from the previous birthing season.
Normally travelling about 19–55 km a day while migrating, the reindeer can run at speeds of 60–80 km/h.
At the end of their journey, they spend the summer feeding on the abundant grasses and plants of the tundra. In these rich grounds, an adult reindeer can eat 5 kg of food each day.
Cows have one calf each year, which can stand after only a few minutes and move on with its mother by the next day.
When the first snows fall each year, they turn back south to spend the winter in more sheltered climes and survive by feeding on lichens.
Reindeer thrive in cold climates. They have hooves that allow them to easily walk on snow and ice unlike deer and moose. Their hollow hairs give them extra insulation from the extreme cold and give increased buoyancy allowing them to easily float. A reindeer can swim at speeds up to 10 km/h and migrating herds will not hesitate to swim across a large lake or broad river.




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