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: 19700
Sea otters mating. The male holds the female's head or nose with his jaws during copulation. Visible scars are often present on females from this behavior. Sea otters have a polygynous mating system. Many males actively defend territories and will mate with females that inhabit their territory or seek out females in estrus if no territory is established. Males and females typically bond for the duration of estrus, or about 3 days.
Species: Sea otter, Enhydra lutris
Location: Elkhorn Slough National Estuarine Research Reserve, Moss Landing, California
Image ID: 21606