The bisons massive head is its most characteristic feature. Its forehead bulges because of its convex-shaped frontal bone. Its shoulder hump, dwindling bowlike to the haunches, is supported by unusually long spinal vertebrae. Over powerful neck and shoulder muscles grows a great shaggy coat of curly brown fur, and over the head, like an immense hood, grows a shock of black hair. Its forequarters are higher and much heavier than its haunches. A mature bull stands about 6 1/2 feet (2 meters) at the shoulder and weighs more than 2,000 pounds (900 kilograms). The bisons horns are short and black. In the male they are thick at the base and taper abruptly to sharp points as they curve outward and upward; the females horns are more slender.
Species: American bison, Bison bison
Location: Yellowstone National Park, Wyoming
Image ID: 13120
A rainbow appears in the spray of Riverside Geyser as it erupts over the Firehole River. Riverside is a very predictable geyser. Its eruptions last 30 minutes, reach heights of 75 feet and are usually spaced about 6 hours apart. Upper Geyser Basin.
Location: Upper Geyser Basin, Yellowstone National Park, Wyoming
Image ID: 13367
Sol Duc Falls. Sol Duc Falls is one of the largest and most beautiful waterfalls in Olympic National Park, seen here from a bridge that crosses the canyon just below the falls. Surrounding the falls is an old-growth forest of hemlocks and douglas firs, some of which are three hundred years in age.
Location: Sol Duc Springs, Olympic National Park, Washington
Image ID: 13747
Upper Yosemite Falls near peak flow in spring. Yosemite Falls, at 2425 feet tall (730m) is the tallest waterfall in North America and fifth tallest in the world. Yosemite Valley.
Location: Yosemite Falls, Yosemite National Park, California
Image ID: 16066
Nevada Falls marks where the Merced River plummets almost 600 through a joint in the Little Yosemite Valley, shooting out from a sheer granite cliff and then down to a boulder pile far below.
Location: Nevada Falls, Yosemite National Park, California
Image ID: 16114
Yosemite Falls rises above the Merced River, viewed from the Swinging Bridge. The 2425 falls is the tallest in North America. Yosemite Valley.
Location: Yosemite Falls, Yosemite National Park, California
Image ID: 16143
Bridalveil Falls with a rainbow forming in its spray, dropping 620 into Yosemite Valley, displaying peak water flow in spring months from deep snowpack and warm weather melt. Yosemite Valley.
Location: Bridalveil Falls, Yosemite National Park, California
Image ID: 16160
Delicate Arch, dusted with snow, at sunset, with the snow-covered La Sal mountains in the distance. Delicate Arch stands 45 feet high, with a span of 33 feet, atop of bowl of slickrock sandstone.
Location: Delicate Arch, Arches National Park, Utah
Image ID: 18104
Coastal brown bear in meadow. The tall sedge grasses in this coastal meadow are a food source for brown bears, who may eat 30 lbs of it each day during summer while waiting for their preferred food, salmon, to arrive in the nearby rivers.
Species: Brown bear, Ursus arctos
Location: Lake Clark National Park, Alaska
Image ID: 19138
Young brown bear grazes in tall sedge grass. Brown bears can consume 30 lbs of sedge grass daily, waiting weeks until spawning salmon fill the rivers.
Species: Brown bear, Ursus arctos
Location: Lake Clark National Park, Alaska
Image ID: 19147
Brown bear cubs. These cubs are one and a half years old and have yet to leave their mother. They will be on their own and have to fend for themselves next summer.
Species: Brown bear, Ursus arctos
Location: Lake Clark National Park, Alaska
Image ID: 19150