Glacier National Park is home to 62 species of mammals, ranging from the tiny pygmy shrew, about the weight of a dime, to majestic species such as the grizzly bear, gray wolf, elk, lynx, wolverine, cougar, mountain goat and bighorn sheep. What's unique about the list is its completeness. Only the woodland caribou and bison are missing . This is due to two things. One, the park was designated early, in 1910, giving wildlife unprecedented protection. The second reason is space. Not only is the park large -- over a million acres -- but the surrounding national forests, wilderness areas and Canadian protected lands ensure that wide-ranging animals such as grizzlies and wolverines have plenty of room to roam.
The lynx and grizzly are threatened species, while the gray wolf is endangered. Fishers and wolverines are rare in Glacier Park. Northern bog lemmings live only in a few wet fen/bogs in the park. But they are all present in a spectacular mix that is unique in the continental U. S.
Grizzlies always attract human attention. Pioneering studies of DNA in hair and scat have given scientists new tools for estimating their numbers in the park. The latest estimates hover just above 300 bears, but refinements are constantly improving the accuracy of the estimate. Grizzlies are large and potentially dangerous animals. Despite their size and strength they feed mostly on plants. Grasses, cow parsnip, glacier lilies, and huckleberries make up the bulk of their diets. At well-defined times of the year they binge on ladybird beetles, army cutworm moths and whitebark pine nuts. Winter-killed carrion supplements their spring diet with much-needed protein. The chronology of when these foods are available is a learned behavior that is passed from the sow to her cubs. Where the bears eat also seems to be a learned behavior. On the east side of Glacier Park some grizzlies spend all summer in the lowland meadows and aspen groves, returning to the high country only to hibernate. Others spend springtime in the valleys, dining on the succulent early growth, but then return to the high country for the rest of the growing season. Studies have shown that feeding habits are not a one-way energy exchange. Grizzlies use their long claws and powerful shoulder muscles to dig for glacier lilies in early summer. The digging releases nitrogen to the soil and glacier lilies in subsequent years are larger and more abundant in grizzly digs. Huckleberry seeds are spread in bear droppings, complete with the perfect fertilizer for germination.
Complexities of the forest food web are also illustrated on a very small scale by the red-backed vole in Glacier Park's west-side old growth forests. The voles eat mostly fungus, so they flourish in the dark undergrowth-free ancient forests of the McDonald Valley. By eating fungus they also spread fungal spores in their travels. The mycorrhizal (rootlets) of fungus permeate the soils in ancient forests, about 2 tons of it per acre, and allow the roots of conifer trees to gather nutrients. No fungus, no forest. No voles, no fungus. No fungus, no voles. The lesson is clear. When even a seemingly obscure species is lost, major upsets to the ecosystem can result. When a species is removed from the system, or a new one introduced, we may spend many years watching the unintended consequences.