In the late spring the wolf sheds his winter coat. The new hair that forms the short summer coat, continues to grow just enough to gradually form the long winter coat. They can also tell from a wolf's track if it is rabid, as it has a tension in the muscles of his feet that keep his footpads spread, when he is walking on dry ground. L. David Mech Wolves in warmer climates have shorter guard hairs and less dense undercoat. The red wolf, which lives in hot, humid areas, has a shorter coat and longer pointed ears, than the wolves of the north.
Short ears are less sensitive to the cold, while long ears are efficient dissipaters of body heat.
When a wolf curls up at night, it uses it's bushy tail to cover it's feet and nose. The tail placed over the nose holds the warm air exhaled from the lungs over the feet and nose, warming them. In extreme cold the wolf can reduce the flow of blood near it's skin to conserve heat. When in contact with ice or snow, the temperature of the wolf's footpads remain at just above the tissue freezing point. The wolf's ability to regulate it's body temperature has helped it to survive in a wide variety of climates.