1. Reindeer can run as fast as 80 kilometers an hour, meaning they could face a speeding ticket in many cities worldwide.
2. Reindeer are the only mammals whose eyes can change color. This is based on the season: they become more golden yellow in summer when the reindeer faces large quantities of solar rays in the northern climates and blue in winter to better see in the frequent darkness.
3. Reindeer are famous for their fondness for hallucinogenic mushrooms. They then release those toxins through their urine, which has made reindeer urine a popular way to get high among some herders.
4. The idea of reindeer pulling Santa Clause's sleigh can be credited to the 1822 poem The Night Before Christmas by Clement Clarke Moore. But prior to that, various tribes had been describing flying reindeer in their folklore for thousands of years. In fact stone etchings of flying reindeer dating back 4,000 years have been found in Mongolia.
5. Reindeer shed their antlers every year only to regrow them the following season.
6. Young reindeer antlers are covered in skin and hair, which dries and peels as they grow larger. That's why reindeer with growing antlers are often found scratching them on trees.
7. Both male and female reindeer grow antlers, which is highly unusual for mammals.
8. Baby reindeer can immediately stand on their feet after birth.
9. Reindeer are great swimmers. They're able to cross wide and powerful streams, as well as the icy ocean, at speeds of up to 9 km/hr.
10. Reindeer are the only mammals that can see ultraviolet light. Humans can detect differences in light waves of around 400 nanometers, while for reindeer the figure is 320 nanometers. This is critical in arctic conditions, where snow can reflect up to 90% of ultraviolet light.