Wednesday’s Wildlife: Bighorn Sheep

Few wildlife sightings capture the spirit of Alberta's Rocky Mountains quite like bighorn sheep. Whether they're balancing on steep cliff faces or grazing along alpine slopes, these remarkable animals have become a symbol of resilience and life in the mountains. In fact, the Rocky Mountain bighorn sheep is Alberta's official provincial mammal.

While many people recognise the impressive curled horns of mature males, there is much more to these mountain specialists than their iconic appearance. Their unique adaptations, complex social lives, and ability to survive in rugged terrain make them among Alberta's most fascinating native mammals.

Life over the edge 

Bighorn sheep live on the eastern slopes of the Rocky Mountains and in the nearby foothills of western Alberta. They depend on open, steep terrain with rocky cliffs and alpine meadows where they can quickly escape predators. Rather than relying on speed alone, bighorn sheep survive by climbing terrain that few other large mammals can navigate.

To help digest tough vegetation, bighorn sheep have a four-part stomach

Their success comes from specialised hooves that act almost like natural climbing shoes. Each hoof has a hard outer edge that grips narrow rock ledges and a soft, textured inner pad that conforms to uneven surfaces, allowing the sheep to maintain remarkable balance on steep cliffs. Their wide-set eyes also provide an exceptional field of vision, helping them detect predators from long distances.

Bighorn sheep don't stay in one place year-round. Many populations make seasonal movements between higher elevations during the summer, where fresh vegetation is plentiful, and lower valleys in winter, where snow is shallower and food is easier to reach.

A distinguished palate 

Like cattle and deer, bighorn sheep are ruminants, meaning they have a four-chambered stomach that helps them digest tough plant material efficiently.

During spring and summer, they primarily graze on grass and flowering plants, taking advantage of nutrient-rich vegetation that emerges after snowmelt. As fall and winter arrive and fresh forage becomes scarce, they shift their diet to shrubs, sagebrush, willow and other woody plants.

Rams perform headbutting contests during mating season, and can take heavy impacts due to their shock-absorbing horns

In Alberta, natural mineral licks also play an important role in their nutrition. Sheep may travel considerable distances to reach these mineral-rich sites, which provide essential nutrients that support growth, reproduction and overall health.

A seasonal social life

Ewes (adult females), lambs and young sheep form nursery bands led by experienced females. Rams (adult males) spend most of the year in bachelor groups, joining females only during the breeding season, known as the rut.

The rut typically occurs in late fall. During this time, mature rams compete for breeding opportunities by establishing dominance. One of the most recognisable behaviours associated with bighorn sheep is the head-butting contest between competing males.

Ewes and rams generally stay separated until the rut, also known as mating season

Although these collisions can sound violent, they are part of a highly ritualised display. Rams may charge toward each other at speeds approaching 65 kilometres per hour before their massive horns collide. Their thick skulls, powerful neck muscles and horn structure help absorb much of the impact, reducing the likelihood of serious injury, although injury still can occur.

Ewes usually give birth to a single lamb in late spring. Lambing often occurs on steep, rugged terrain that offers protection from predators during the vulnerable first weeks of life. Within just a day or two, newborn lambs are already capable climbers, following their mothers across rocky terrain.

Predators in the mountains 

Despite their impressive climbing abilities, bighorn sheep remain an important prey species in Alberta's mountain ecosystems.

Their primary predators include cougars and wolves, and occasionally include grizzly bears and black bears. Younger sheep may be predated upon by coyotes and golden eagles. The steep terrain bighorn sheep inhabit provides their greatest defence. When threatened, they can rapidly climb narrow ledges and rocky cliffs that predators often cannot safely access. Living in groups also provides added protection, as multiple animals can watch for danger while others feed.

Other challenges

While predators have always been part of the bighorn sheep's environment, many of today's greatest challenges come from human activity.

One of the most significant threats is the transmission of disease from domestic sheep and goats. Bighorn sheep are highly susceptible to respiratory diseases, particularly pneumonia caused by bacteria commonly carried by domestic livestock. Even brief contact between wild and domestic sheep or goats can introduce pathogens that cause severe disease outbreaks. Entire herds have experienced dramatic declines following these infections, making disease management a major conservation priority across Alberta.

Like trees, you can tell a ram's age by counting the "rings" on its horns

Habitat fragmentation also creates challenges. Roads, recreational infrastructure, and other development can disrupt seasonal movements and reduce access to important winter ranges or mineral licks. Human disturbance may also increase stress, particularly during lambing season or harsh winters when animals have limited energy reserves.

Engaging in wildlife etiquette 

One of the best parts of exploring Alberta's mountain parks is the opportunity to see wildlife in their natural habitat. Bighorn sheep are frequently spotted in places such as Kananaskis Country, Banff National Park, Jasper National Park and along mountain highways.

If you're lucky enough to encounter them, remember that giving wildlife space is one of the best ways to protect them.

An adult ram's horns can weigh up to 30 pounds

Never approach bighorn sheep for a closer photo or encourage them to come near by offering food. Feeding wildlife changes their natural behaviour, increases the risk of vehicle collisions and can expose animals to dangerous human interactions.

If sheep are standing beside roads, remain inside your vehicle whenever possible and avoid blocking traffic or surrounding the animals. Depending on the time of year and location within the province, stopping on the side of the road to look at wildlife can come with fines and penalties. National parks often establish "no stopping zones" in certain areas during peak wildlife season. If you are able to stop safely and legally, use binoculars.

Keep dogs leashed in areas where wildlife may be present. Even well-behaved pets can stress wild animals or cause them to flee into dangerous terrain. Bighorn sheep can significantly maim or kill domestic dogs when defending their territory or young. 

A mountain icon

With their remarkable climbing abilities, bighorn sheep remain one of the most iconic and adaptable animals in Alberta. 

By respecting their space, staying on designated trails and supporting healthy mountain habitats, we can help ensure future generations continue to experience the unforgettable sight of Alberta's provincial mammal.

For assistance with injured and orphaned wildlife, please contact the Calgary Wildlife Rehabilitation Society at 403-214-1312.

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References

Alberta Environment and Protected Areas. (n.d.). Bighorn sheep management. Government of Alberta. https://www.alberta.ca/bighorn-sheep-management

Alberta Environment and Protected Areas. (n.d.). Bighorn sheep disease surveillance. Government of Alberta. https://www.alberta.ca/bighorn-sheep-disease-surveillance

Alberta Environment and Protected Areas. (n.d.). Pneumonia and bighorn sheep. Government of Alberta. https://www.alberta.ca/pneumonia-and-bighorn-sheep

University of British Columbia, Faculty of Forestry. (2018). Mountain ungulates and habitat ecology research. https://forestry.ubc.ca

University of Alberta. (n.d.). Alberta Biodiversity Monitoring Institute: Bighorn sheep species profile. https://abmi.ca/home/species.html