Roosevelt elk, adult bull male with large antlers. This bull elk has recently shed the velvet that covers its antlers. While an antler is growing, it is covered with highly vascular skin called velvet, which supplies oxygen and nutrients to the growing bone; once the antler has achieved its full size, the velvet is lost and the antler's bone dies. This dead bone structure is the mature antler, which is itself shed after each mating season. Roosevelt elk grow to 10' and 1300 lb, eating grasses, sedges and various berries, inhabiting the coastal rainforests of the Pacific Northwest.
Species: Roosevelt elk, Cervus canadensis roosevelti
Location: Redwood National Park, California
Image ID: 26389
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: 19715
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: 19719
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: 19722
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
A sea otter eats a clam that it has taken from the shallow sandy bottom of Elkhorn Slough. Because sea otters have such a high metabolic rate, they eat up to 30% of their body weight each day in the form of clams, mussels, urchins, crabs and abalone. Sea otters are the only known tool-using marine mammal, using a stone or old shell to open the shells of their prey as they float on their backs.
Species: Sea otter, Enhydra lutris
Location: Elkhorn Slough National Estuarine Research Reserve, Moss Landing, California
Image ID: 21622