While there are many different species of lemmings, they all share the same general physical characteristics. Since their natural habitat is in the frigid northern climes, the lemming must consistently battle cold temperatures. In order to make this fight more efficient, the lemmings'body has evolved into a relatively compact form — its snub nose and short legs and tail provide an efficiency that we humans cannot claim. While our blood has to make the long trek to distant fingers and toes, the lemming's rounded, rodent-like body provides for easy flow and, thus, easier heating.
Another method of fighting the cold is the lemmings'living quarters. In the long and harsh winter months, they construct elaborate tunnel systems under the snow. To assist in the voluminous amounts of digging needed in order to prepare for the winter months, the lemming has evolved a pair of long claws on its front feet that grow in the late fall and are lost in the spring. When they do venture out from their subterranean world, their coat has taken on a lighter shade, in some varieties completely white, and will serve as protection from its natural predators — the wolverine, Arctic and red foxes, and a variety of birds. The Inuit have also been known to use their hides for a variety of things.
Though there is a bit of a mystery to it, the primary reason the lemmings migrate is to find food and, as mentioned earlier, decrease over-population. Because female lemmings are capable of giving birth after only a month of their own birth, over-population is a serious problem. Researchers who have observed this mass migration have noted the amazing sounds that these little animals, traveling in such large groups, produce, describing it as a sort of whistling that ebbs and flows with the approach of each "herd." In one instance, researchers calculated that a group of migrating lemmings averaged 15 km a day. It is this breakneck speed, carried out by such a small animal, that literally causes many to die. The population is further depleted by females who stop along the way to give birth and take care of their young. And of course, many others blindly run into bodies of water that are in their migratory path.
Additional Resources:A member of the IAP has suggested the following book as a great resource. The book details scientific information about snow crystals, how animals and people survive in the snow and how native peoples (Inuit) of the Arctic regions have many different vocabulary words to describe different types of snow. The book is titled,The Secret Language of Snow, written by Terry Tempest Williams.
Jack Hanna's Animal Adventure TV show produced a half-hour special about how the IAP dogs are trained and their interaction with the team members. This episode, "Mush!" (#2042) can be ordered for U.S. $14.95 plus $4.75 shipping and handling by calling 1-800-51-HANNA.