Grand Teton National Park


The Teton Range dominates Grand Teton National Park, attracting the attention of all who pass through Jackson Hole. The geologic processes that resulted in mountain building and sculpting also have determined where plants grow in the park. Herbivores—plant-eating animals like moose, mule deer and elk—occur where their food source exists. Carnivores—meat eating animals like bears, coyotes and weasels—follow the herbivores they prey upon. Geologic events created the dramatic scenery of Jackson Hole and indirectly account for the distribution and abundance of wildlife and plants found here.

The Tetons owe their existence to movement along a fault found where the mountains meet the valley. Starting 5 - 9 million years ago, movement along the fault with massive earthquakes occurred every thousand years or so. The mountain block uplifted on the west side of the fault while the valley block dropped-down east of the fault. Today the mountains rise more than a mile above Jackson Hole, with total displacement of 30,000 feet along the fault.

Ice performed the sculpting and carving of the Tetons. As recently as 15,000 years ago, small mountain glaciers or rivers of ice flowed from high elevation cirques and gouged out U-shaped canyons between the peaks. Mountain glaciers spilled from the canyons to the valley floor, forming basins occupied today by lakes like Leigh, Jenny, Bradley, Taggart and Phelps. Ridges of glacial debris, called moraines, surround these lakes and mark the edge of the glacier's flow.

While small glaciers flowed in the Teton Range, a massive glacier covered much of what is now Yellowstone National Park 25,000 years ago. This river of ice flowed south, forming the depression that Jackson Lake fills today, and carried debris as far as Snake River Overlook, eight miles north of Moose on Highway 26-89-191. Today moraines support forests of lodgepole pine and other conifers. Elk and black bear seek refuge and shade in morainal forests and graze in nearby meadows during cooler parts of the day.

When the climate warmed and glacial ice melted, water broke through the moraines and swirled souththrough the valley, carrying away soil. Today the southern part of Jackson Hole contains poor, dry, rockysoils. Only vegetation like sagebrush and certain grasses and wildflowers can thrive in such desert likeconditions. Despite the hot and dry conditions, some mammals and birds favor the sagebrush flats. Bisongraze on grasses growing among the sagebrush, while pronghorns eat sagebrush itself. Sage grouse, largechicken-like birds, eat sagebrush buds.

For the past 10,000 years or so, the Snake River has cut through glacial moraines and flowed fromJackson Lake to the southern end of Jackson Hole. Old river terraces paralleling today's Snake Riverindicate that the Snake carried much more water in the past.

Along the Snake River grow cottonwoods and blue spruces where bald eagles nest. Beavers occasionallydam side channels of the Snake River, establishing ponds that Canada geese and ducks use for nesting andfeeding. Moose and beavers eat willows that flourish in wetlands along the river. Willows and otherwetland plants provide cover and nest sites for a multitude of songbirds.

As you explore Grand Teton National Park, read its landscape. Note the work of glaciers on themountains and canyons and the old river terraces carved in the past by the Snake River. Watch forwildlife. The presence of wildlife provides clues to the ancient processes that formed and shaped thisarea.

The diversity of wildlife communities in Grand Teton National Park and the John D. Rockefeller, Jr. Memorial Parkway complements the spectacular scenery. Part of the Greater Yellowstone Ecosystem, the two National Park Service areas offer wildlife a variety of habitats. Each habitat must supply the basic needs of wildlife: food, water, cover and living space. Familiarity with the habitats and habits of park and parkway wildlife results in increased viewing opportunities.

Habitat Types

Wind and snow limit life above treeline (about 10,000 feet). Some plants and animals have adapted to the harsh conditions. Plants are mat-like, animals are few. Look for yellow-bellied marmots, pikas and bighorn sheep.

The most widespread habitat type in the park, sagebrush flats occur on dry, porous soils. More than 100 species of grasses and wildflowers grow along with abundant sagebrush. Lack of cover makes large animals conspicuous. Look for pronghorns, coyotes, bison, badgers, elk and Uinta ground squirrels.

From treeline to valley floor, forests provide cover and food for many mammal species. Lodgepole pines dominate, but forests also contain firs, aspens and spruces. Look for elk, mule deer, martens, red squirrels, black bears and snowshoe hares.

Rivers, Lakes and Ponds
Aquatic habitats and adjacent forests, marshes and meadows fulfill the needs of many forms of wildlife. Diverse and abundant vegetation offers excellent food and cover. Water is plentiful. Look for moose, river otters, beavers, muskrats, coyotes, bison and mule deer.


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