Male elk (bull) alongside female elk in grassy meadow, during rutting season. A bull will defend his harem of 20 cows or more from competing bulls and predators. Only mature bulls have large harems and breeding success peaks at about eight years of age. Bulls between two to four years and over 11 years of age rarely have harems, and spend most of the rut on the periphery of larger harems. Young and old bulls that do acquire a harem hold it later in the breeding season than do bulls in their prime. A bull with a harem rarely feeds and he may lose up to 20 percent of his body weight while he is guarding the harem.
Species: Elk, Cervus canadensis
Location: Yellowstone National Park, Wyoming
Image ID: 19723
Bull elk, with large antlers, alongside female elk during rutting season, autumn. A bull will defend his harem of 20 cows or more from competing bulls and predators. Only mature bulls have large harems and breeding success peaks at about eight years of age. Bulls between two to four years and over 11 years of age rarely have harems, and spend most of the rut on the periphery of larger harems. Young and old bulls that do acquire a harem hold it later in the breeding season than do bulls in their prime. A bull with a harem rarely feeds and he may lose up to 20 percent of his body weight while he is guarding the harem.
Species: Elk, Cervus canadensis
Location: Yellowstone National Park, Wyoming
Image ID: 19724
Bull elk in sage brush with large rack of antlers during the fall rut (mating season). This bull elk has sparred with other bulls to establish his harem of females with which he hopes to mate.
Species: Elk, Cervus canadensis
Location: Mammoth Hot Springs, Yellowstone National Park, Wyoming
Image ID: 19746
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: Madison River, Yellowstone National Park, Wyoming
Image ID: 19781
Bull elk, with large antlers, alongside female elk during rutting season, autumn. A bull will defend his harem of 20 cows or more from competing bulls and predators. Only mature bulls have large harems and breeding success peaks at about eight years of age. Bulls between two to four years and over 11 years of age rarely have harems, and spend most of the rut on the periphery of larger harems. Young and old bulls that do acquire a harem hold it later in the breeding season than do bulls in their prime. A bull with a harem rarely feeds and he may lose up to 20 percent of his body weight while he is guarding the harem.
Species: Elk, Cervus canadensis
Location: Yellowstone National Park, Wyoming
Image ID: 19782
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: 19788
Excelsior Geyser, now dormant, was formerly the worlds largest geyser. It still produces immense runoff into the Firehole River: 4,500 gallons per minute, or 6 million gallons per day. It is located in Midway Geyser Basin.
Location: Midway Geyser Basin, Yellowstone National Park, Wyoming
Image ID: 26953
Bacteria mats and Grand Prismatic Spring. The orange color is due to bacteria which thrive only on the cooler fringes of the hot spring, while the hotter center of the spring hosts blue-colored bacteria.
Location: Midway Geyser Basin, Yellowstone National Park, Wyoming
Image ID: 26954
Morning Glory Pool, has long been considered a must-see site in Yellowstone. At one time a road brought visitors to its brink. Over the years they threw coins, bottles and trash in the pool, reducing its flow and causing the red and orange bacteria to creep in from its edge, replacing the blue bacteria that thrive in the hotter water at the center of the pool. The pool is now accessed only by a foot path.
Location: Upper Geyser Basin, Yellowstone National Park, Wyoming
Image ID: 26955
Bacteria mats and Grand Prismatic Spring. The orange color is due to bacteria which thrive only on the cooler fringes of the hot spring, while the hotter center of the spring hosts blue-colored bacteria.
Location: Midway Geyser Basin, Yellowstone National Park, Wyoming
Image ID: 26958
Panorama dimensions: 4624 x 8376
Panorama of Excelsior Geyser, now dormant, was formerly the worlds largest geyser. It still produces immense runoff into the Firehole River: 4,500 gallons per minute, or 6 million gallons per day. It is located in Midway Geyser Basin.
Location: Midway Geyser Basin, Yellowstone National Park, Wyoming
Image ID: 26959
Panorama dimensions: 5188 x 10216
Bacteria mats and Grand Prismatic Spring. The orange color is due to bacteria which thrive only on the cooler fringes of the hot spring, while the hotter center of the spring hosts blue-colored bacteria.
Location: Midway Geyser Basin, Yellowstone National Park, Wyoming
Image ID: 26964
Coyote crosses a road in front of a car. Dozens of coyotes, wolves, bears, elk and bison are killed each year in Yellowstone as they attempt to cross the roads in front of drivers who are not paying attention or speeding.
Species: Coyote, Canis latrans
Location: Yellowstone National Park, Wyoming
Image ID: 19649
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: 19694
Bull elk, with large antlers, alongside female elk during rutting season, autumn. A bull will defend his harem of 20 cows or more from competing bulls and predators. Only mature bulls have large harems and breeding success peaks at about eight years of age. Bulls between two to four years and over 11 years of age rarely have harems, and spend most of the rut on the periphery of larger harems. Young and old bulls that do acquire a harem hold it later in the breeding season than do bulls in their prime. A bull with a harem rarely feeds and he may lose up to 20 percent of his body weight while he is guarding the harem.
Species: Elk, Cervus canadensis
Location: Yellowstone National Park, Wyoming
Image ID: 19696
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: 19705
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: Madison River, Yellowstone National Park, Wyoming
Image ID: 19711
Bull elk in sage brush with large rack of antlers during the fall rut (mating season). This bull elk has sparred with other bulls to establish his harem of females with which he hopes to mate.
Species: Elk, Cervus canadensis
Location: Mammoth Hot Springs, Yellowstone National Park, Wyoming
Image ID: 19726
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: Yellowstone National Park, Wyoming
Image ID: 19729
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: Yellowstone National Park, Wyoming
Image ID: 19731
Bull elk in sage brush with large rack of antlers during the fall rut (mating season). This bull elk has sparred with other bulls to establish his harem of females with which he hopes to mate.
Species: Elk, Cervus canadensis
Location: Mammoth Hot Springs, Yellowstone National Park, Wyoming
Image ID: 19735
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: 19736
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: Yellowstone National Park, Wyoming
Image ID: 19737
Elk, bull elk, adult male elk with large set of antlers. By September, this bull elk's antlers have reached their full size and the velvet has fallen off. This bull elk has sparred with other bulls for access to herds of females in estrous and ready to mate.
Species: Elk, Cervus canadensis
Location: Yellowstone National Park, Wyoming
Image ID: 19739