Game animals · Side by side
Bighorn Sheep vs Dall Sheep
How to tell them apart
Quick answer
Check the coat and the horns: a Dall sheep is white with slim, amber horns that flare out away from the face, while a bighorn is brown with a white rump and heavy, dark-brown horns that curl tight around the ear. A dark Stone's sheep is still a thinhorn; look for those slender, flaring amber horns.
Bighorn and Dall sheep are North America's two wild sheep species, close relatives descended from sheep that crossed the Bering land bridge from Asia. They seldom share a mountain, but anyone chasing a sheep Grand Slam, judging a mount or sorting through trail-camera and travel photos needs to tell them apart, and the dark Stone's sheep form of the thinhorn makes it harder than it sounds.
Key differences
| Trait | Bighorn Sheep | Dall Sheep |
|---|---|---|
| Coat | Grayish to chocolate brown with a white rump and muzzle | White (Dall) or charcoal with a white rump (Stone's) |
| Ram horns | Massive, dark brown, curling tight around the ear | Slimmer, amber, in an open curl that flares outward |
| Ram weight | Averages about 230 lb, can top 300 | Roughly 160–250 lb |
| Range | Alberta and British Columbia south to Mexico | Alaska, Yukon, western NWT and northern British Columbia |
| Habitat | Mountains, foothills, badlands and desert ranges | Dry alpine ridges, meadows and cliffs |
| Rut | Peaks November into early December | Late November into early December |
| Boone and Crockett record | 216 3/8 (Montana pickup, 2016) | 189 6/8 (Alaska, 1961) |
Where each lives
The two species split the continent north and south. Bighorns live from the Rockies of Alberta and British Columbia south through the western states, with the desert bighorn in hot, dry ranges from Nevada and California to West Texas and northwestern Mexico, and even in North Dakota's badlands. Thinhorn sheep take over in the far north: white Dall sheep in Alaska, the Yukon and the Mackenzie Mountains, and dark Stone's sheep in northern British Columbia. Outside a zoo, you are very unlikely to see both on the same mountain.
Stone's sheep and other in-betweens
Coat color is what confuses people. Stone's sheep are thinhorns in a dark coat, gray to nearly black with a white rump and belly, and at a glance they can look like a bighorn. Intermediate 'Fannin' sheep in the Yukon mix white and gray. The horns are the tiebreaker: every thinhorn carries slimmer, amber horns that spiral wide, while a bighorn's are massive and brown. The two species have also been known to hybridize, one reason biologists still debate exactly how distinct they are.
Hunting each one
In the lower 48, bighorn tags come through lotteries that can take decades to draw, plus a few auction and raffle tags that raise large sums for conservation. Dall and Stone's sheep hunts are remote fly-in or backpack hunts in Alaska and northern Canada, where nonresidents generally need a guide. Both require top fitness and careful horn judging, and both reward the effort with some of the finest wild meat there is. Check current regulations for each hunt.
By the numbers
The traits the daily hunt game compares for each.
| Clue | Bighorn Sheep | Dall Sheep |
|---|---|---|
| Type | Big game | Big game |
| Habitat | Mountains | Mountains |
| Headgear | Horns | Horns |
| Region | Western mountains | Arctic tundra |
| Typical weight | 250 lb | 200 lb |
| Diet | Herbivore | Herbivore |
FAQ
Can bighorn and Dall sheep interbreed?
Yes, the two have hybridized, which is one reason taxonomists debate how distinct they are. Because they mostly live in separate mountain ranges, a hunter is very unlikely to see a hybrid.
Is a Stone's sheep a bighorn?
No. Stone's sheep are a dark subspecies of the thinhorn sheep, the same species as the Dall. Their slender, flaring amber horns give them away even though their coat is dark like a bighorn's.
Which is bigger, a bighorn or a Dall sheep?
Bighorns. A mature Rocky Mountain ram averages about 230 pounds and carries far heavier horns, while Dall rams run roughly 160 to 250 pounds. Desert bighorns are smaller than Rocky Mountain bighorns.
What is the Grand Slam of North American sheep?
It means taking all four kinds of North American wild sheep: the Rocky Mountain bighorn, the desert bighorn, the Dall sheep and the Stone's sheep.
Could you tell them apart from a few clues? Test yourself in today's puzzle.
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