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Kootenay National Park

Rocky Mountain Bighorn Sheep

A year in the life


After a gestation period between 150 – 180 days, pregnant ewes isolate themselves to give birth to 1-2 lambs on steep cliffs. This dispersal across steep terrain makes it difficult for predators to key in on the vulnerable young. After about a week, lambs return with their mothers to nursery herds consisting of ewes and juveniles. Rams form separate herds.

A close-up view of a small bighorn sheep lamb peeking around its mum's front flank.
Lamb beside mum
© Parks Canada


Ram and nursery herds remain apart high on mountainside meadows.

A close herd of bighorn sheep ewes with young grazing on a steep, grassy slope.
Ewe group on grassland
© Parks Canada/A. Dibb


Ram and nursery herds rejoin. During the mating season or rut, rams battle for dominance and access to individual females. Spectacular, ritual battles between dominant males result.

Two bighorn sheep rams knock horns on a rocky, grass slope silhouetted against blue, snowy mountains.
Two rams battle during the rut
© Parks Canada


The mixed herd moves to lower elevation winter ranges. As winter ranges tend to be in valley bottoms, competition with human activity and development often results. It is possible for people and wild sheep to co-exist if we accommodate the needs of wild sheep for winter range and seasonal migration routes.

A view of a large, ground level, yellow, diamond shaped sign sporting the silhouettes of three sheep and the words 'wildlife crossing' and 'next 3 km' in French and English.
Sheep warning sign
© Parks Canada/A. Dibb
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Rocky Mountain Bighorn Sheep