Glacier National Park is home to 71 species of mammals, ranging from the tiny pygmy shrew, about the weight of a dime, to large majestic species like elk, which weigh upwards of 500 pounds. What's unique about Glacier's ecosystem is it is intact and relatively undisturbed. This is due to two things: 1.) the park was designated early, in 1910, giving wildlife over a century of protection; and 2.) 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.
Glacier supports nine species of bats, the most common being the little brown bat. The only mammal capable of sustained flight, bat species in Montana are insectivores able to consume one third of their body weight in insects during their nocturnal feeding periods. Since their appearance 52.5 million years ago, many bat species have developed sophisticated echolocation mechanisms to find their prey in the dark via sound waves. With the approach of winter, some bat species fly to warmer areas, while others remain to find safe roosting sites and go into torpor, slowing their body functions down until roused by warm weather. Waterton-Glacier has the most substantial migration route currently known for Hoary Bats across North America.
Recent outbreaks of White-nose Syndrome, which has killed more than 5 million bats in the eastern US, has sparked bat studies in the West. Bat surveys in Waterton-Glacier have resulted in the discovery of three species previously unobserved in the region.
Bears have always attracted human attention. When many people think of Glacier, they think of bears. Glacier provides the core of one of the largest remaining grizzly bear populations in the lower 48 states.
Beaver Castor canadensis
North America's largest rodent is known for its stick and log construction. They are semi-aquatic, building their lodges and dam on rivers and streams. They are herbivores with webbed hind feet and chisel-like teeth for chewing wood. In Glacier, Lower McDonald Creek is a great place to see beavers. When alarmed, beavers will make their presence known by aggressively slapping the water surface with their large flat tails. Some of the first Anglo traders came to the area to the hunt and trap the beaver for its prized pelt. Read about how beavers impact their environment.
Bighorn Sheep Ovis canadensis
Rocky Mountain bighorn sheep, named for their large horns that can weigh up to 30 pounds on males, inhabit alpine meadows and grassy mountain slopes in the Rocky Mountains of Canada and the United States. Their ability to climb steep terrain allows them to find cover from predators. Traveling in flocks and feeding on grasses and shrubs throughout the year, they are one of the few species that can survive winters at high elevations.
Elk Cervus canadensis
One of the largest land mammals in North America, elk range in forest and forest-edge habitat, feeding on grasses, plants, leaves, and bark. Remaining at higher elevations during the summer, they move to lower refuges in the fall, sometimes traveling scores of miles to winter feeding grounds. Mating season, or the rut, occurs between late August and December when dominant males attract a harem by a show of large antlers and ritual sparring with competitors. The male’s characteristic bugle call is often heard during this time.
Lynx Lynx canadensis
Rarely seen in the continental United States, and listed as a threatened species in the lower 48 states, the Canada lynx does frequent portions of Glacier. More than twice the size of a domestic cat, lynx prefer the shelter of dense forests. They hunt in higher elevations, where their long legs and broad furred feet aid them in traveling through deep snow, using their large ears and eyes to find prey. Snowshoe hares comprise 60% to 97% of their diet, with rodents, birds and sometimes larger animals, and occasional carrion, making up the rest. While prominently solitary, females and their cubs have been known to work together in hunting, one lynx scaring prey out of hiding while the others attack.
Mountain Goats Oreamnos americanus
Dwelling in the cliffs at high elevations throughout the year, the mountain goat, also known as the Rocky Mountain goat, is well suited for survival in the mountains. With two layers of wool, a dense undercoat covered by an outer layer of long hollow hairs, the species can survive temperatures as low as minus 50 degrees Fahrenheit and winds of 100 mph. Specialized cloven hooves with traction-creating inner pads and dewclaws provide sure footing on steep slopes of up to 60 degrees, beyond the reach of most predators. If threatened, they use their size, agility, and horns to protect themselves. Herbivores with a diet of grasses, herbs, sedges, moss, lichen, twigs, and even foliage from conifers, mountain goats have the ability to stay in the alpine through the winter months.
Mountain Lions Felis concolor
The mountain lion is the largest feline in North America. Although not commonly seen, they persist in stable densities throughout Glacier. Read about mountain lion safety before hitting the trail. As one of Glacier’s larger predators, mountain lions pursue a wide variety of prey, including deer, elk, moose, and bighorn sheep, as well as smaller animals. They usually hunt at night, dawn, or dusk, and after a successful hunt, will hide large carcasses and feed on them for several days.
Mountain lions can be found in most habitat types, but tend to prefer wooded areas where they can utilize cover for sneaking up on prey. With the exceptions of mating, and when females are raising young, mountain lions are solitary and elusive. They have one of the largest home ranges of any mammal in the Western Hemisphere. These home ranges include areas to hunt and rest, sources for water, lookout positions, and denning sites where cubs can be safely reared.
Pikas Ochotona princeps
Pikas are one of the few animals able to survive winters in the alpine. Solitary herbivores, they spend the summer months gathering plant materials and storing them under rock enclosures. Known as haystacks, these collections of grasses, sedges, twigs, moss and flowers allow them to endure the harsh climate of the mountains without having to hibernate or go to lower elevations. The pika’s small size, about 4 inches (10 cm), allows it to find cover under rocks in talus slopes to avoid predators such as weasels and birds of prey. With grey to brown fur and round ears, they can also blend in with their rocky surroundings.
Highly sensitive to temperatures above 78 degrees Fahrenheit, pikas are seen as a species highly susceptible to climate change impacts. Surveys of pika populations are currently underway.
Wolverines Gulo gulo
Wolverines are the largest member of the weasel family and tend to prefer subalpine fir forests in isolated, remote wilderness with ample spring snow cover. Short, stocky legs with five-toed paws give wolverines the ability to travel easily through snow, and its thick, oily fur is resistant to frost. With powerful jaws and sharp claws, wolverines are opportunistic predators and scavengers. Scat analyses show that a large portion of a wolverine’s diet consists of large mammals such as deer and elk that are mostly scavenged. In addition, they hunt animals such as ground squirrels, marmots, snowshoe hares, and mice, and will supplement their diet with insect and plant material.
Highly nomadic, wolverines travel great distances in search of food or mates during breeding season. Large ranges and very low population densities are factors influencing the species vulnerability to habitat disturbance, habitat fragmentation, trapping, and climate change. Researchers have documented more than 50 wolverines in Glacier National Park, showing the densest population of this species in the lower 48 states.