Male elk bugling during the fall rut. Large male elk are known as bulls. Male elk have large antlers which are shed each year. Male elk engage in competitive mating behaviors during the rut, including posturing, antler wrestling and bugling, a loud series of screams which is intended to establish dominance over other males and attract females.
Species: Elk, Cervus canadensis
Location: Mammoth Hot Springs, Yellowstone National Park, Wyoming
Image ID: 19693
A rainbow appears in the mist of the Lower Falls of the Yellowstone River. At 308 feet, the Lower Falls of the Yellowstone River is the tallest fall in the park. This view is from Lookout Point on the North side of the Grand Canyon of the Yellowstone. When conditions are perfect in midsummer, a midmorning rainbow briefly appears in the falls.
Location: Grand Canyon of the Yellowstone, Yellowstone National Park, Wyoming
Image ID: 13319
Grand Prismatic Spring (left) and Excelsior Geyser (right). Grand Prismatic Spring displays a stunning rainbow of colors created by species of thermophilac (heat-loving) bacteria that thrive in narrow temperature ranges. The blue water in the center is too hot to support any bacterial life, while the outer orange rings are the coolest water. Grand Prismatic Spring is the largest spring in the United States and the third-largest in the world. Midway Geyser Basin.
Location: Midway Geyser Basin, Yellowstone National Park, Wyoming
Image ID: 13571
A large, old brown bear (grizzly bear) wades across Brooks River. Coastal and near-coastal brown bears in Alaska can live to 25 years of age, weigh up to 1400 lbs and stand over 9 feet tall.
Species: Brown bear, Ursus arctos
Location: Brooks River, Katmai National Park, Alaska
Image ID: 17039
Old Faithful geyser, sunrise. Reaching up to 185' in height and lasting up to 5 minutes, Old Faithful geyser is the most famous geyser in the world and the first geyser in Yellowstone to be named.
Location: Upper Geyser Basin, Yellowstone National Park, Wyoming
Image ID: 26939
Portrait of a young brown bear, pausing while grazing 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: 19135
Huge California Sea Lion Male Underwater, a bull, patrolling his breeding harem and territory, Coronado Islands, Mexico. His sagittal crest, the bony bump on his head that distinguishes adult male sea lions, is clearly seen. This particular sea lion bears an orange tag on his left foreflipper, probably as a result of rescue and release as a young sea lion years earlier.
Species: California sea lion, Zalophus californianus
Location: Coronado Islands (Islas Coronado), Baja California, Mexico
Image ID: 38655
Lower Falls of the Yellowstone River. At 308 feet, the Lower Falls of the Yellowstone River is the tallest fall in the park. This view is from the famous and popular Artist Point on the south side of the Grand Canyon of the Yellowstone.
Location: Grand Canyon of the Yellowstone, Yellowstone National Park, Wyoming
Image ID: 07769
Lower Falls of the Yellowstone River. At 308 feet, the Lower Falls of the Yellowstone River is the tallest fall in the park. This view is from the famous and popular Artist Point on the south side of the Grand Canyon of the Yellowstone.
Location: Grand Canyon of the Yellowstone, Yellowstone National Park, Wyoming
Image ID: 07770
Lower Falls of the Yellowstone River. At 308 feet, the Lower Falls of the Yellowstone River is the tallest fall in the park. This view is from the famous and popular Artist Point on the south side of the Grand Canyon of the Yellowstone.
Location: Grand Canyon of the Yellowstone, Yellowstone National Park, Wyoming
Image ID: 07771
Black bear walking in a grassy meadow. Black bears can live 25 years or more, and range in color from deepest black to chocolate and cinnamon brown. Adult males typically weigh up to 600 pounds. Adult females weight up to 400 pounds and reach sexual maturity at 3 or 4 years of age. Adults stand about 3' tall at the shoulder.
Species: American black bear, Ursus americanus
Location: Orr, Minnesota
Image ID: 18744
Huge California Sea Lion Male Underwater, a bull, patrolling his breeding harem and territory, Coronado Islands, Mexico. His sagittal crest, the bony bump on his head that distinguishes adult male sea lions, is clearly seen. This particular sea lion bears an orange tag on his left foreflipper, probably as a result of rescue and release as a young sea lion years earlier.
Species: California sea lion, Zalophus californianus
Location: Coronado Islands (Islas Coronado), Baja California, Mexico
Image ID: 38657
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
Black bear walking in a grassy meadow. Black bears can live 25 years or more, and range in color from deepest black to chocolate and cinnamon brown. Adult males typically weigh up to 600 pounds. Adult females weight up to 400 pounds and reach sexual maturity at 3 or 4 years of age. Adults stand about 3' tall at the shoulder.
Species: American black bear, Ursus americanus
Location: Orr, Minnesota
Image ID: 18741
Black bear walking in a grassy meadow. Black bears can live 25 years or more, and range in color from deepest black to chocolate and cinnamon brown. Adult males typically weigh up to 600 pounds. Adult females weight up to 400 pounds and reach sexual maturity at 3 or 4 years of age. Adults stand about 3' tall at the shoulder.
Species: American black bear, Ursus americanus
Location: Orr, Minnesota
Image ID: 18743
Black bear in a tree. Black bears are expert tree climbers and will ascend trees if they sense danger or the approach of larger bears, to seek a place to rest, or to get a view of their surroundings.
Species: American black bear, Ursus americanus
Location: Orr, Minnesota
Image ID: 18745
Black bear cub in a tree. Mother bears will often send their cubs up into the safety of a tree if larger bears (who might seek to injure the cubs) are nearby. Black bears have sharp claws and, in spite of their size, are expert tree climbers.
Species: American black bear, Ursus americanus
Location: Orr, Minnesota
Image ID: 18746
Black bear in a tree. Black bears are expert tree climbers and will ascend trees if they sense danger or the approach of larger bears, to seek a place to rest, or to get a view of their surroundings.
Species: American black bear, Ursus americanus
Location: Orr, Minnesota
Image ID: 18747
Black bear walking in a grassy meadow. Black bears can live 25 years or more, and range in color from deepest black to chocolate and cinnamon brown. Adult males typically weigh up to 600 pounds. Adult females weight up to 400 pounds and reach sexual maturity at 3 or 4 years of age. Adults stand about 3' tall at the shoulder.
Species: American black bear, Ursus americanus
Location: Orr, Minnesota
Image ID: 18748
Black bear walking in a grassy meadow. Black bears can live 25 years or more, and range in color from deepest black to chocolate and cinnamon brown. Adult males typically weigh up to 600 pounds. Adult females weight up to 400 pounds and reach sexual maturity at 3 or 4 years of age. Adults stand about 3' tall at the shoulder.
Species: American black bear, Ursus americanus
Location: Orr, Minnesota
Image ID: 18749