The pronghorn and sage grouse characterize the wide open sage and grassland community, whose purpose otherwise seems simply to provide the Teton Range a foreground. This world is alive with small birds feeding on masses of insects and spiders. These songbirds, along with gophers, mice, and snakes, provide the diet for weasels, hawks, and ravens. The sage grouse depends largely on the evergreen sagebrush for food. The pronghorns depend on it part-time, being unable to subsist on grasses alone. This is North America’s fastest mammal, able to run at more than 45 miles per hour. For added security it boasts oversize lungs and windpipe, and the largest eyes by body weight of any mammal. Faster yet is the prairie falcon that hunts these flats, streaking out of the sky at speeds up to 200 miles per hour. An aspen grove of only 27 trunks may shelter more than 12 pairs of birds—house wrens, mountain bluebirds, swallows, and woodpeckers. It may also shelter an understory of young spruce and fir that could one day replace it. Deer and elk wander out of the forest to browse the aspen, which can produce more than 2.5 tons dry weight of vegetation per acre. Ironically, aspen have suffered somewhat in the park for lack of forest fires. It turns out that fire suppression suppresses aspens, which recover burned areas quickly. In respect of natural processes, the park now practices wildfire management instead of complete suppression, except where human life and private property might be threatened. The alpine world (see pages 36-37) stands as magic for some. Its lilliputian scale fascinates. A tiny rabbit, the pika (or cony), gathers grasses there all summer in miniature haystacks you may discover. The yellow-bellied marmot, on the other hand, stores fat, its body being adapted to pass the winter in hibernation. Surprising numbers of insects are found there. And spiders wander the snowfields to feed on cold-sluggish insects blown up from warmer elevations. Diminutive alpine creatures aren’t seen from a car, but much of the park’s wildlife bounty reveals itself to casual observers. The national park tries to offer the wild community a haven where natural processes can work, but this is no simple task. The park includes only portions of some creatures’ annual ranges. And underlying the ideal balance of natural processes are complex relationships we only gradually unravel. Mammals [Illustration: _Bobcat_] [Illustration: _Weasel_] [Illustration: _Yellow-bellied marmots_] [Illustration: _Pika_] [Illustration: _Moose_] [Illustration: _Deer mouse_] [Illustration: _Coyote_] [Illustration: _Elk calf_] [Illustration: _Badger_] [Illustration: _Black bear_] [Illustration: _Snowshoe Hare_] [Illustration: _Pronghorn (antelope)_] [Illustration: _Mule Deer_] [Illustration: _Uinta ground squirrel_] [Illustration: _Beaver_] [Illustration: _Porcupine_]