Get Wild: Colorado’s awesome state mammal could use a little help

Frances Hartogh
Get Wild
The Gore Range Rocky Mountain bighorn sheep herd has occupied its winter range above east Vail since before humans occupied the valley.
Richard Seeley/Get Wild

Just over Vail Pass in Eagle County, a group of concerned citizens is trying to preserve the last-remaining winter habitat for a herd of Rocky Mountain bighorn sheep. Known technically as the S2 Gore Range Bighorn herd, the sheep have overwintered on the land, locally known as Booth Heights, for millennia. So, what’s the big deal about saving these bighorns?

First, Rocky Mountain bighorns are incredibly cool animals, which is why in 1961 Colorado declared them our state mammal. Native to Colorado, Ovis canadensis, with their massive, coiled horns and superb climbing ability, are only found in the Rockies. Up to 6 feet long and 250 pounds, Rocky Mountain bighorns are nevertheless expert rock climbers. Pads on two-toed hooves provide traction, and those toes spread apart providing extra climbing stability. Watching bighorns — even baby lambs — scale vertical cliffs is an amazing experience.

To see some amazing footage of our local bighorns, visit

A male ram’s horns can weigh up to 30 pounds. Thickly ridged with growth rings, which tell a sheep’s age, horns aren’t shed. Ram’s horns reach “full curl” around 7-8 years. Females, called ewes, have slender, spikey horns.

What do rams do with those magnificent horns? Come fall, rams charge each other at speeds up to 20 mph, participating in head-butting contests to establish dominance. How do rams survive these battles, which can last up to 20 hours? Double-layered skulls are honeycombed with bone struts, and thick tendons link skull and spine to help recoil from impact.

So, why the focus on preserving the winter habitat of this particular herd? What makes the Gore Range herd extra special is that it is one of — and perhaps the only — remaining native herd in our state. By the early 1900s, Rocky Mountain bighorns had dwindled due to unregulated hunting and diseases introduced through European livestock. In the 1940s, Colorado Parks and Wildlife began conducting bighorn reintroductions, like those near Georgetown. But our Gore Range herd has occupied its winter range above east Vail since before humans ever occupied the valley!

Two bighorn species live in Colorado. Desert bighorns were introduced near Colorado National Monument in 1979. But only our Rocky Mountain bighorn is native.

Colorado declared Rocky Mountain bighorn sheep to be its state mammal in 1961.
Richard Seeley/Get Wild

Bighorns need year-round territory with two important things: grazing and access to rocky terrain providing escape routes. In summer, the Gore Range bighorns graze in the high-Alpine tundra, meadows and open woodlands of the Eagles Nest Wilderness, with nearby cliffs providing protection. 

But in winter, bighorns must descend to open south-facing slopes with rocky outcrops and cliffs, where low snowpack allows grazing and cliffs provide haven from predators. With open south-facing slopes topped by rocky outcrops, the Gore Range bighorn’s winter habitat above east Vail is ideal, and is the last-remaining winter habitat available to them. 

This habitat has featured prominently in recent news due to a proposal to construct much-needed employee housing there. Colorado Parks and Wildlife says that the herd “simply won’t exist” if the proposed development occurs. The Town of Vail must decide at its Oct. 3 meeting whether adequate funding and public support exists for acquiring the habitat as permanent open space. 

Bighorns’ natural predators include coyotes, mountain lions and even eagles. However, the biggest threats to bighorns are loss of habitat to human development, pneumonia contracted from domestic sheep and competition from non-native, introduced species like mountain goats that also carry pneumonia pathogens lethal to bighorns. 

Learn more about the time-critical efforts to save our Gore Range bighorn winter habitat at Vail Bighorn Sheep Initiative, and ways the public can help.

Frances Hartogh
Frances Hartogh/Courtesy photo

“Get Wild” publishes on Fridays in the Summit Daily News. Frances Hartogh is a volunteer wilderness ranger for the Eagle-Summit Wilderness Alliance.

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