Sheep 101

  • Desert Bighorn Sheep

    (Ovis canadensis nelsoni)

    3 Rams standing next to each other
  • Rocky Mountain Bighorn Sheep
    Image of a Rocky Mountain Bighorn Sheep
    • ● Scientific name: Ovis canadensis canadensis
    • ● Rams can weigh over 300 lbs
    • ● Horns have tight curls
    • ● Thicker double layered coats
    • ● Live in alpine meadows, mountain slopes and foothills
    Desert Bighorn Sheep
    Image of a Desert Bighorn Sheep
    • ● Scientific name: Ovis canadensis nelsoni
    • ● Rams weigh less than 240 lbs
    • ● Longer horns, sometimes very wide
    • ● Thinner coats with less hair on belly
    • ● Live in the arid southwestern mountain foothills and canyonlands
  • Males are called Rams
    Example of a Ram looking into the distance
  • Females are called Ewes
    Example of an Ewe looking at the camera
  • The young are called Lambs
    Example of a Lamb
  • Desert Bighorn Sheep are adapted for cold winters and hot summers because their body temperature can fluctuate several degrees.
    Image of sheep in snow during winter
    Image of sheep shown in the summer
  • Bighorn sheep are very nimble on rocky, steep terrain because they have specially adapted hooves. Their hooves are concave and have hard edges with a soft, rubber like pad that allows them to cling to as little as a two inch ledge!
    An image of a hoove
  • Bighorn Sheep are “Ruminants”. This means that they can eat a lot of grass at one time. Then they find a safe place to re-chew it; absorbing as many nutrients as they can.
    Image of 3 Ewes resting in the shade
  • Desert Bighorn Sheep have a 9 stage digestive system that helps them get as many nutrients as possible from the desert vegetation.
    Image of an Ewe grazing on grass
  • Most people know that Bighorn Sheep use their horns for fighting. However, they also use them as tools to remove the spines and break open cactus to get to the moisture rich pulp inside.
  • In the Summer, Bighorn Sheep eat mostly grasses and sedges
    A group of ewes grazing along the side of a road
  • In the Winter, Bighorn Sheep eat mostly woody plants and shrubs.
    Ewe grazing on some shrubs next to a rock wall
  • Desert Bighorn Sheep have excellent eyesight and can see a predator moving from over a mile!
    Two rams staring straight ahead
  • Bighorn sheep are well adapted to their desert home. They can lose up to 30% of their body weight in water and still survive. That’s more than a camel!
  • Bighorn Sheep are one of the most abundant symbols in ancient Native American petroglyphs and pictographs.
  • A Ram’s horns can weigh over 30 pounds! That’s more than the rest of their skeleton combined!
    Close up of a Ram's horns
  • "Sometimes a ram's horns will grow into his line of sight. The ram may rub or break off the tips of his horns to improve his vision. This is called "Brooming".
    Side view of a Ram's head showing horn effecting it's eye sight
  • Because their horns grow throughout their life, you can count the annual rings to determine age just like a tree!
    Close up a Ram's horn showing the different rings
  • A bighorn’s skull is double layered and reinforced with a honeycomb structure of bone struts to protect their brain from the tremendous blows of combat.
    Two bighorns dueling each other
  • If you uncurled a big ram’s horns they would be over three feet long with a circumference at the base of more than a foot!
    3 Rams standing together on a ridge
  • Rams separate from ewes and lambs for most of the year. They come together in late Summer/early Fall for the breeding season.
  • When Males are 2-4 years old, they must go off and find a bachelor herd of other males. Sometimes, if they can’t find other males, they will join the herd of another species like mule deer or even cows!
  • The gestation time for Desert Bighorns is about 6 months. The lambs are usually born in late Winter.
  • The lambs are “precocious” meaning that they can run and jump as well as their mother in about a day or so.
  • Lambs only drink their mother’s milk for 4 to 6 months.
  • Several Sheep in Colorado National Monument are equipped with radio tracking collars to help biologist study their movements.
    Ram wearing a tracking collar
  • Colorado National Monument is a sanctuary for Desert Bighorn Sheep
  • because…
    • ● They do not have to compete with livestock or feral burros and horses.
    • ● They are not hunted.
    • ● They are separated from domestic sheep that carry diseases.
    • ● Their preferred habitat of steep, rocky, terrain is abundant, providing them with areas for grazing, bedding, lambing, and escape from predators.
    • ● They are monitored by wildlife biologists to make sure their populations remain healthy.
  • Bighorn Sheep are vulnerable to these predators:
    Image of a Mountain Lion

    Mountain Lion

    Image of a Black Bear

    Black Bear

    Image of a Bobcat

    Bobcats

    Image of a Coyote

    Coyotes

    Image of a Golden Eagle

    Golden Eagles

  • 8 different sub-species of bighorn sheep have been identified:
    • ● Ovis canadensis canadensis (Rocky mountain bighorn)
    • ● Ovis canadensis californiana (California bighorn)
    • ● Ovis canadensis mexicana (Mexican desert bighorn)
    • ● Ovis canadensis nelsoni (Nelson's Peninsular bighorn)
    • ● Ovis canadensis weemsi (Weem's desert bighorn)
    • ● Ovis canadensis cremnobates (Peninsular desert bighorn sheep) Endangered
    • ● Ovis canadensis sierrae (Sierra Nevada bighorn sheep) Endangered
    • ● Ovis canadensis auduboni (Audubon's bighorn sheep) Extinct
  • After near-extinction, Desert Bighorn Sheep repopulation efforts have been successful in many areas. Hopefully, they will delight visitors to the Colorado National Monument for many years to come.