My, What Big Horns You Have!

One of the species on my list of things to find on my Yellowstone trip was the Rocky Mountain bighorn sheep. I didn’t have to look far.

The bighorn sheep is a North American mammal known for its, you guessed it, rather impressive horns. The males (rams) are especially well, um, endowed with large curved horns that can weight up to 30 lb (14 kg) just by themselves, or about half the bone weight of the animal. Ewes (females) also have horns, but they are shorter and without as much curvature. The Rocky Mountain bighorns can sometimes exceed 500 lb (230 kg) for males and 200 lb (90 kg) for females. That’s a lot of sheep, but in Yellowstone, the average size is quite a bit less than that. Approximately 379 bighorns were thought to be in the park in 2012.

A bighorn sheep contemplates his next move, in Yellowstone National Park, Wyoming.

Besides their famous big horns, these sheep are known for being pretty good at hanging on to the side of steep cliffs, where they seek a degree of protection from predators. It doesn’t always work out, though, as cougars are not much impressed by this strategy, being quite agile themselves. And, well, sometimes the poor guys just fall off the cliff. Hey, they might be sure-footed, but they’re not perfect!

A bighorn sheep relaxes where it feels safest, on the side of a cliff, in Yellowstone National Park, Wyoming.

I mentioned that I didn’t have to look far to find the bighorns. While I was at a turnout with a group of wolf watchers, staring at tiny little wolves way across the valley through spotting scopes and a super-telephoto lens, a herd of bighorns started appearing above us on the steep hill beside the turnout. It wasn’t long before the hillside was covered in sheep, and as they grazed on the grasses that were covered in only a light snow, they seemed to take no interest in us at all. As they came closer to the road, I fully expected one ram to walk right into the back of one of the vans parked there, he got so close to the open doors.

A herd of bighorn sheep chows down on grasses on the side of a hill, in Yellowstone National Park, Wyoming.

Looking back on it, I think the sheep were employing much the same strategy as the coyotes I mentioned in a recent article. Some of their enemies, the wolves and the cougars at least, are very shy around humans, and avoid roads and other areas where humans hang out. The bighorns, just like the coyotes, have figured out that they’re safer around humans than not, at least in Yellowstone National Park where hunting is not allowed.

A male bighorn sheep forages for lunch on the side of a hill, in Yellowstone National Park, Wyoming.

I definitely have to give them some credit for this behavior, as I don’t think it’s an accident. With only a few hundred in the entire huge park, I sure saw a lot of bighorns at different locations along the road in Lamar Valley the week I was there. Part of it has to do with the Lamar Valley being lower in elevation, where the lower levels of snow cover make it easier to forage. But when they get close enough to look through our spotting scopes to check out the wolves’ location across the road, I think perhaps they’re on to something!

A bighorn sheep poses for the camera, in Yellowstone National Park, Wyoming.