Caribou Adaptations
...bou benefit from long legs for speed, support on rough ground, traveling through deep snow, and swimming; however, because of a special circulation adaptation they don’t suffer from the negative consequence of heat loss usually associated with length. The veins and arteries within their legs run close together, reducing heat loss in their body. The warm blood pumping from the heart transfers heat to the cooler venous blood moving up the leg. Therefore, the body temperature remains at 104ºF, while legs need less energy to maintain a cooler temperature of 50ºF (Pielou, 1994). Two crescent-shaped toes on each hoof support the Caribou’s weight (they have 4 toes on each hoof, 2 small “dew claws” and two larger toes). The nails of these hooves grow long and sharp in the winter to provide traction on the slick ice and to protect the hoof pads. As winter approaches, the thick, fleshy hoof pads shrink becoming thin and hard. The body preserves heat as only the nails touch the frozen ground, while the hoof pad remains above the nails nestled among long hair between the toes. (Journey North, 2002). Caribou survive largely on low-growing lichen during the winter. A complex digestive system allows the Caribou to extract the most energy out of the nutrie...