Bighorn Sheep – My Wildlife Wonders No. 2

Posted on Posted onBy Heather
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Once pushed to the brink by overhunting, habitat loss and disease, bighorn sheep have made a strong comeback, thanks to decades of conservation work across the western U.S. and Canada. However, population growth has plateaued and constant vigilance is necessary to maintain stability, and several subspecies remain at-risk.

Species: Bighorn Sheep

Also Known As: Rocky Mountain bighorn, desert bighorn, mountain sheep

Three bighorn sheep stand among tall golden grasses and scattered gray boulders in a rugged, mountainous landscape. Two large rams dominate the foreground, their massive, spiraled horns curling back majestically from their foreheads. The ram on the left faces sideways, alert and powerful, while the one on the right looks directly at the camera with an intense, steady gaze, muscles taut as if frozen mid-step. Both have thick, tan coats with darker shading around their shoulders and necks. A third, lighter-colored sheep grazes in the background with its head lowered, partially hidden behind the rams. Behind them, the terrain is dotted with shrubs, leafless branches, and hints of green foliage, signaling early spring or late fall in the wild. The atmosphere feels raw and windswept, steeped in the quiet tension of the high country.

Once numbering between 1.5 and 2 million in North America, bighorn sheep populations plummeted in the 19th and 20th centuries due to overhunting, habitat loss, disease transmission from domestic livestock, and fragmentation of their rugged mountain habitats. By the mid-20th century, the population had dropped as low as 25,000. Many herds had vanished from historic ranges, and several subspecies, including the Sierra Nevada and Peninsular bighorn, were federally listed as endangered. Today, bighorn sheep remain a symbol of North America’s wildest landscapes, but their survival is challenged by ongoing threats such as disease outbreaks, climate extremes and competition with domestic animals.

A bighorn sheep ewe and her lamb stand side by side in a grassy, shrubby meadow in Rocky Mountain National Park. The ewe, slightly larger and a pale beige color with a thick but patchy coat in its spring molt, grazes quietly behind the younger sheep. In front of her stands her lamb, smaller and more alert, with a sleeker, warmer tan coat and shorter, gently curved horns beginning to grow. The lamb gazes to the left with soft, curious eyes, its ears perked in quiet attentiveness. Around them, young green shrubs and dry grasses poke up from the earth, and the muted tones of early spring or late autumn wrap the landscape in a hushed stillness. The pair stands close together, evoking a sense of quiet protection and gentle watchfulness in the wild.

The story of the bighorn sheep is now one North America tells of resilience and recovery, though their population lurks between 70,000 to 87,000, and their range is limited to less than 10 percent what it was at its height. Targeted conservation efforts have included translocations, disease management and habitat restoration. Collaborative partnerships among wildlife agencies, nonprofits and Indigenous communities have helped stabilize or increase many populations.

In California alone, more than 5,000 bighorn sheep now roam from desert canyons to alpine peaks according to recent population surveys, while restoration projects in places like Texas and the Sierra Nevada have reestablished herds in areas where they disappeared for generations. Continued science-based management and community engagement remain essential for ensuring that this iconic species endures in the wild for generations to come.

A lone male bighorn sheep ram stands in profile among dense shrubs and grasses in Rocky Mountain National Park, his thick, muscular body partially turned to reveal his powerful frame. His fur is a dusty beige with subtle patches of darker brown along his chest and legs, and his massive horns curl in wide, full spirals from the top of his head, deeply ridged with years of growth. The ram’s strong jawline and broad snout give him a dignified, almost regal appearance, while his dark eyes gaze calmly ahead, scanning the terrain. Surrounding him is a tangle of green-leafed bushes, dry grasses, and faded wildflowers in an early spring or late autumn landscape. The setting is quiet and wild, evoking the rugged, solitary strength of the high-altitude wilderness he calls home.

Range & Habitat

A stylized map highlights the western region of North America in dark blue, enclosed in a sharp geometric frame on a yellow-orange background. The zoomed-in section shows the Pacific-facing states and provinces of the United States, Canada, and Mexico, extending from Alaska and British Columbia in the north, down through the U.S. West Coast and Rocky Mountain states, and into central Mexico. The highlighted area includes states like California, Oregon, Washington, Arizona, Utah, and parts of others stretching eastward into the Great Plains. The bold navy shape dramatically contrasts against the pale basemap, creating a striking visual focus on the North American western corridor. The background map faintly displays the surrounding continents in lighter tones, reinforcing the regional spotlight effect.
  • Origin: The bighorn sheep originated from wild sheep in Eurasia, specifically Siberian snow sheep, that migrated to North America during the Pleistocene epoch. This migration occurred via the Bering Land Bridge, a land connection that existed between Siberia and Alaska during periods of lower sea levels. The timing of this migration is estimated to be between 100,000 and over 1 million years ago.
  • Range: The current range of the bighorn sheep is primarily limited to fragmented populations across the mountainous regions of western North America, extending from southern Canada through the western United States and into northern Mexico.
  • Habitat: They inhabit steep, rocky mountain terrain, including cliffs, canyons and plateaus. Desert bighorn sheep also live on desert slopes and washes. Their elevation range varies seasonally and by subspecies, from low-elevation desert habitats (400 to 4,000 feet) for Peninsular bighorn sheep to high-elevation alpine and subalpine zones (1,500 to 4,300 meters) for Rocky Mountain and Sierra Nevada populations.

Quick Facts About the Bighorn Sheep

  • Order: Artiodactyla (even-toed ungulates)
  • Family: Bovidae (buffalo, cattle, sheep, goats)
  • Genus: Ovis
  • Species: Ovis canadensis.
  • Subspecies:
    • Rocky Mountain bighorn sheep (O. c. canadensis)
    • Sierra Nevada bighorn sheep (O. c. sierrae) – federally endangered
    • Desert bighorn sheep (O. c. nelsoni), includes the endangered Peninsular population segment
  • Diet: Grasses, sedges, forbs, shrubs (herbivorous)
  • Height: 30 to 41 inches (at the shoulder)
  • Weight: 100 to 300 pounds (females), 160 to 320 pounds (males). Rare males have been reported at 500 pounds.
  • Lifespan: 7 to 15 years in the wild
  • Sexual Maturity: 2 to 3 years
  • Natural Predators: Mountain lions, wolves, coyotes, golden eagles (lambs)

Mating

  • Mating System: Polygynous; dominant males mate with multiple females during the breeding season
  • Mating Season: Rut occurs in autumn and early winter; typically late September through December (varies by region and subspecies)
  • Courtship Displays: Males engage in head-butting contests to establish dominance, display their horn size and pursue ewes. Dominant rams follow and guard estrous females, perform low grunts, and may nuzzle or sniff the female before mating.

Reproduction

  • Gestation Period: 5 to 6 months (150 to 180 days)
  • Offspring: Typically a single lamb; twins are rare but have been reported. Lambs are usually born in the spring or early summer, coinciding with better forage availability. Early months are critical, with ewes often isolating themselves to give birth and protect the lamb from predators.
  • Nursing: Ewes nurse their lambs for about 4 to 7 months, depending on environmental conditions and lamb development. Lambs gradually transition to grazing but continue nursing for several months to gain strength and immunity.
A powerful male bighorn sheep ram stands still in a scrubby meadow in Rocky Mountain National Park, facing slightly left with his head turned toward the camera. His thick, muscular body is cloaked in a coarse, tan-brown coat that darkens along his chest and neck. Dominating his face are two massive, curled horns that spiral outward and downward from his skull, ridged with deep grooves that mark his age and battles. His nose is white and slightly scarred, and his amber-brown eyes hold a calm, steady intensity, as if sizing up the viewer. Short, weathered shrubs and green foliage blur into the background, hinting at the mountainous terrain he calls home. The air feels crisp and wild, and the ram’s presence commands quiet respect, a symbol of strength and survival in the high alpine wilderness.

Conservation Status

Stable
(Last assessed by IUCN 2019)

The IUCN Red List currently lists bighorn sheep as “Least Concern” overall, but the Sierra Nevada and Peninsular bighorn sheep are federally listed as endangered in the U.S.

  • Key Threats: Bighorn sheep face significant threats from habitat loss and fragmentation, disease transmission from domestic livestock (especially pneumonia), competition with domestic and feral animals, invasive plant species and human disturbance. Small, isolated populations are particularly vulnerable to local extinctions and genetic problems.
  • Conservation Efforts: Conservation strategies have included protecting and restoring habitats, managing and reducing disease risks from livestock, reintroducing and augmenting populations, and engaging in research and public education. Cooperation among wildlife agencies, local communities and landowners has helped some populations recover, though ongoing management is essential for their continued survival.

Wildlife Snapshot: Bighorn Sheep

Discover the remarkable journey of the bighorn sheep and its vital role in North American ecosystems. Explore our infographic for a quick overview of bighorn sheep traits, conservation status, and why protecting this iconic species matters.

Wildlife snapshot infographic about bighorn sheep including photos, maps, graphics, illustrations, facts and figures about the species

Coloring Sheet & Activities for Kids

Click below to download free, fun activities and coloring sheets for kids to enjoy and learn more iconic North American species like the Bighorn sheep!

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Preview image of My Wildlife Wonders bighorn sheep coloring book page and activities sheet for kids free download and printable

Printing tip: These pages are designed for 8.5″ x 11″ (Letter) size paper, standard in U.S. printers. Select “Fit to page” (or similar) in your printer dialog menu to ensure all the contents are printed. Choose “Point on Both Sides” or “Print 2-Sided” to reduce paper waste.

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