08/30/2026
A GPS-collared bighorn ram walked 400 miles alone from Colorado to Wyoming's Laramie Mountains in 71 days, passed through five herds without joining any of them, and turned around on Christmas Eve.
Colorado Parks and Wildlife had collared him on July 7, 2009, between the towns of Granby and Tabernash in Grand County. He was five years old, healthy, and alone. Nasal swabs tested negative for mycoplasma, parainfluenza, and hemolytic pasteurella. Those results would matter later.
He was living in lodgepole pine habitat at roughly 8,100 to 9,300 feet, 12 miles from the nearest herd in any direction, in a pocket of suitable terrain between the Georgetown herd to the south and the St. Vrain herd to the north. He had been observed there alone for seven months before anyone collared him. After collaring, he sat for three more months. His GPS uploaded six locations per day by satellite. Every fix landed within six miles of the capture site.
On October 19, the data changed. The rut was beginning in nearby herds. A five-year-old ram is old enough to breed but young enough to be subordinate to every established male in his home range. If he could not breed where he was, the instinct said walk. So he did.
He averaged seven miles per day. On five days he covered more than 12 miles. His maximum was 17 miles in a single day, crossing open sagebrush flats in Wyoming where he had no escape terrain, no cliffs, and no cover. During the journey, 96 percent of his Wyoming locations fell outside modeled bighorn habitat. He was spending nearly all of his time in terrain that wildlife managers classify as unsuitable for his species.
He passed through the Gore and Flattops herds in Colorado. Then the Encampment River, Douglas Creek, and Laramie Peak herds in Wyoming. He did not stop at any of them. He also passed through numerous domestic sheep grazing allotments in both states. He was spotted by humans exactly twice during the entire 400-mile journey. One observer took a photograph near Hayden, Colorado. Without the GPS collar uploading his position every few hours, nobody would have known the trip actually happened.
On December 24, he reached the farthest point of his journey in the Laramie Mountains. Then he turned around. He walked four miles back along his own trail over four days and stopped. He stayed within three-quarters of a mile of that spot for two weeks. He was not moving. Whatever he had been looking for across 400 miles and five herds, he had not found it. The journey appeared to be over. He seemed to be resting before heading back home.
CPW had been tracking his satellite uploads the entire time and informed Wyoming Game and Fish when he crossed the state line.
Then on January 11, 2010, Wyoming Game and Fish crew hiked in and shot the ram. Gunshot wounds of the thoracic cavity. They killed him to prevent him from contacting Wyoming's bighorn herds and potentially transmitting pathogens.
The decision had a rationale that anyone managing bighorn sheep in the American West would recognize. When respiratory pathogens from domestic sheep enter a wild bighorn herd, the result is not a few sick animals. It is a catastrophic die-off that can kill 50 to 90 percent of the herd within months. Entire herds have been erased by a single contact event between one domestic sheep and one bighorn. The Granby ram had walked through numerous domestic sheep grazing allotments across two states over 71 days.
CPW's original nasal swabs in July were clean. But that was four months and 400 miles ago. If he was carrying something now and walked into the Laramie Peak herd, Wyoming could lose the herd. The state's protocol for a wandering bighorn that has passed through domestic sheep country and is approaching a healthy wild herd is not to wait and test. It is to remove the animal before contact happens. Wyoming simply followed the protocol.
Sherri Huwer and Karin Eichhoff published the full GPS record at the 19th Biennial Symposium of the Northern Wild Sheep and Goat Council in 2014. The collar recorded 1,059 locations. The researchers wrote that they did not know of any previously documented bighorn sheep movement of this magnitude.
Image is for illustration purposes only
Source: Huwer and Eichhoff (2014), 19th Biennial Symposium of the Northern Wild Sheep and Goat Council / Colorado Parks and Wildlife / Wyoming Game and Fish Department.
