Open slopes are the terrain of grizzly bears, elk and bighorn sheep; most animals that live in the park inhabit the grasslands and open forest of the montane zone. Marsh areas in the low-lying parts provide excellent habitat for moose, which can weigh up to 500 kilograms, beaver and waterfowl. Conservationists, such as the controversial naturalist, Grey Owl, in the 1930's saved the beaver, trapped to near extinction for its pelt. Today they can be seen around Pyramid Beach or the Valley of the Five Lakes building lodges and dams and eating the bark of the trembling aspen. Cougars and the smaller lynx have been sighted in the park but both are very rare. Porcupine, wood rat, marmot, squirrel and deer mouse are also montane residents. Canada's grizzly (or brown) bear, the biggest and most easily recognized for the pronounced hump on its back, is neither slow nor limited in its range. Strong enough to kill an elk and drag it uphill or swim in rapids to catch salmon, it is never tame or harmless. People and wolves are their only predators. Sadly the grizzly has been extirpated in many of its original habitats and parks such as Jasper may offer its only chance for survival. Black bears are smaller, darker, less endangered, but no less dangerous. Both eat plants, fruit and fish, but will chase down and kill live animals in their Rocky Mountain habitat. In the upper alpine region lives the hairy marmot whose piercing whistle provided the name for the Whistlers just east of the town of Jasper. About 2000 bighorn sheep and considerably fewer mountain goats live in the park and can often be sighted from the roadways. Wolves hunt the elk, deer, caribou and moose. The coyote, smaller than the wolf, has a bushier tail and a yappy bark; foxes are very rare. Mule deer and elk commonly appear on the open slopes, while the dwindling population of mountain caribou is being carefully monitored and protected by the park. The populations of rodents, golden mantled ground squirrel and rock rabbit attract a number of birds of prey: bald eagle, golden eagle, great horned owl, osprey, falcon and several types of hawk. The ptarmigan, grouse, jays and hummingbirds all live here. Rainbow trout, northern pike and stickleback are common in the park®s lakes and watersheds.