The migratory animals can roam 125 miles (200 kilometers) or more in the spring from their winter grazing grounds in the forests to reach calving grounds high in the mountains.
"On hot summer days, they migrate vertically ... until they reach snow patches where the temperature is lower, then back to the valleys, to graze during the midnight sun," says Vannar.
WARM AND WOOLY
Reindeer are also uniquely adapted to survive the harsh Lapland winters, explains Mari Heikkila, director of Ranua Wildlife Park in Finland.
"The hair of the reindeer is hollow, so there is air between the hairs and also inside the hair, and their winter coat is really thick," Heikkila says.
That makes them super-insulated, one reason why Samis have always made their winter clothes from reindeer hides.
Reindeer also have large hooves compared to moose or deer. When the snow is deep, they spread their hooves and make them even wider to stop themselves from sinking in.
EYES THAT CHANGE COLOR
Reindeer eyes change color between summer and winter to adapt to the widely varying levels of light in the high north.
"The reflection from reindeer eyes is yellow-green in summer ... but deep blue in winter," says Karl-Arne Stokkan, a professor at the University of Tromsoe in Norway, part of a scientific team that discovered earlier this year why that is.
Due to the extremely limited light in the far northern winter, reindeer's eyes need to be much more sensitive to light then than in summer. The blue color during the darkest months of the year helps scatter more incoming light and results in better vision, says Stokkan.
TASTY AND HEALTHY