Desert Bighorn is native to the deserts of the United States and this particular yearling ewe lives in Bighorn NWR in a lake which straddles the Montana / Wyoming border. Several females and young band together and graze, while the male band hangs out in separate groups most of the year until mating season arrives. Males fight for the right to father the next generation. Gestation lasts 150–180 days, and the lambs are usually born in late winter.
These critters walk and run on very flexible split hooves, allowing excellent grip for hillside grazing and rock climbing. Desert Bighorn wander all across the high desert areas of the western USA from Montana south to the Mojave, Death Valley, Sonoran Desert.
Stocky, heavy-bodied sheep, similar in size to mule deer, adults males weight in at 115 to 280 pounds, ewes a bit smaller. Their lifespan runs about fifteen or twenty years in the wild. Bighorns forms small male bands and female bands, and live very social lives.
Both genders develop horns soon after birth, and grow throughout life. Older rams have curling horns measuring over three feet long with more than one foot of circumference at the base. The ewes’ horns are much smaller and lighter and do not tend to curl. Both rams and ewes use their horns as tools to break open cactus, which they eat, as well as grasses, bush leaves and buds.
The desert bighorn has become well adapted to living in the desert heat and cold and, unlike most mammals, their body temperature can safely fluctuate several degrees. During the heat of the day, they often rest in the shade of trees and caves. Desert Bighorn adapted to survive for days and days with no water and dehydrate, then drink when they find it, and recover body hydration quickly.
Desert bighorn sheep biologically adapted to a desert mountain environment with little or no permanent water. Some may go without visiting water for weeks, gaining body moisture from food and occasional rainwater the collects in the rocky terrain. Bighorn can lose up to thirty percent of body weight and still survive. After finding and drinking water, they quickly recover.
