The desert bighorn sheep (Ovis canadensis nelsoni) is Nevada’s state animal and is the largest animal that lives in the deserts of North America. The characteristics and behavior of desert bighorn sheep are similar to that of other species of bighorn sheep, except that desert bighorn sheep can go for extended periods of time without drinking water.
Desert bighorn are similar in size to mule deer. Mature rams range weigh between 125 to 200 pounds, while females are somewhat smaller. Due to their unique concave elastic hooves, bighorn are able to climb the steep, rocky terrain of the steep desert mountains with speed and agility. Bighorn rely on their keen eyesight to detect potential predators such as mountain lions, bobcats and coyote. They use their extraordinary climbing ability to escape threats.
Both rams and ewes develop horns soon after birth, with horn growth continuing more or less throughout life. Older rams have impressive sets of 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. After eight years of growth, the horns of an adult ram may weigh more than 30 pounds. Annual growth rings indicate the animal’s age. The rams may rub their own horns in order to improve their field of view. Both rams and ewes use their horns as tools to break open cactus and also for fighting.
Desert bighorn sheep typically live for approximately 10–20 years. The typical diet of a desert bighorn sheep is mainly a variety of grassed. When grasses are unavailable, they turn to other food sources, such as cacti. Desert bighorn sheep are social, forming herds of 8 to 10 individuals. Sometimes herds of 100 are observed in the wild.
Rams battle to determine dominance, which then gains possession of the ewes. Facing each other, rams charge head-on from distances of 20 or more feet, crashing their massive horns together with great impact, until one or the other surrenders.
Bighorns live in separate ram and ewe bands most of the year. They gather during mating season (usually July–October), but breeding may occur anytime in the desert due to suitable climatic conditions. Gestation lasts from 150–180 days, and the lambs are usually born in late winter.
It is not uncommon to see herds of desert bighorn sheep at Valley of Fire, especially in the late afternoon. They are often spotted in and around the Rainbow Vista area and also just before the west entrance to the park. A lone ram is frequently spotted grazing along the main park road.