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Dasher and Dancer and Prancer and Vixen have no doubt been keeping an eye on the thermometer this winter. Reindeer numbers have dropped nearly 60 percent in the last three decades due to climate change and habitat disturbance caused by humans, a study earlier this year found.
The decline of reindeer is a hot topic to more than just Santa and millions of children around the world.
"The caribou is central to the normal function of northern ecosystems," Justina Ray, executive director of Wildlife Conservation Society-Canada, said in 2008. "With their huge range requirements and need for intact landscapes, these animals are serving as the litmus test for whether we will succeed in taking care of their needs in an area that is under intensifying pressure."
Here are some reindeer facts that might surprise you.
They're actually caribouSlide 2 of 13
They're actually caribou
Reindeer and Caribou are two names for the same species (Rangifer tarandus), with reindeer generally referring to the domesticated variety that are herded by humans and pull sleds. Such reindeer live mostly in Scandinavia and Siberia and are typically smaller with shorter legs than their wild caribou relatives. In Siberia, caribou are called "wild" reindeer. The animal's size and weight varies by gender and age, with adult caribou reaching 3 to 4 feet tall (about 1 meter) and weighing on average up to 375 pounds (170 kg) for males and 200 pounds (90 kg) for females.Slide 3 of 13
They get aroundSlide 4 of 13
They get around
Caribou are known to travel up to 3,000 miles (nearly 5,000 km) in a year, the longest documented movements of any terrestrial mammal, according to the IUCN. Their counterpart in the water, the humpback whale, holds the record for the longest mammalian voyage, swimming 5,000 miles (8,000 km) to their balmy breeding grounds in winter. [Top 10 Most Incredible Animal Journeys]Slide 5 of 13
They're fastSlide 6 of 13
While they may not fly, scientists say caribou can run as fast as 48 mph (80 km per hour), though their normal walk is a slow one. When alarmed by a predator, however, a caribou will trot with its head held high and parallel to the ground, and its normally floppy tail held up in the air. When chased, it will gallop quickly.
(Shown above, racing reindeer in the Festival of the North in Russia.)Slide 7 of 13
They can handle the coldSlide 8 of 13