A Semitruck Slammed into a Herd of Bison near Yellowstone National Park

A gory auto wreck west of Yellowstone National Park last week left 13 bison dead and authorities scratching their heads.

According to law enforcement, a semitruck traveling along U.S. Highway 191 smashed into a herd of the animals on Wednesday, December 28, at approximately 6:30 P.M just north of the town of West Yellowstone, Montana. In a statement published on Facebook on Friday, December 30, local police said the initial collision killed multiple bison, and several others had to be euthanized due to severe injuries.

“We deal with wildlife being struck and killed on the roadways in our area on a regular basis due to the abundance of wildlife in our area and our close proximity to Yellowstone National Park,” the statement said. “We are always saddened by any of these incidents, particularly when so many animals are lost.”

Cops said bison often congregate along Highway 191 and the junction with U.S. Highway 297, which is located between the park’s westernmost boundary and the banks of Hebgen Lake. The animals sometimes use the roadway as travel corridors when snowdrifts get too high, authorities said.

Yellowstone’s bison population fluctuates from approximately 3,200 to 5,500 animals and is composed of two primary herds; one lives in the park’s central Hayden and Pelican Valleys during the summer, while another lives in the Lamar Valley, in the park’s northeast corner.

Bison are migratory and may walk as many as 1,000 miles each year to graze, raise offspring, and avoid extreme weather. Those inside the park’s boundaries spend the spring and summer months in mountainous grasslands. In the fall and winter, they head for lower elevations. According to a Park Service report on bison migratory patterns, the central herd traditionally leaves the Hayden and Pelican Valleys and moves west into the Firehole River drainage, and often some of its members continue heading west toward Hebgen Lake and West Yellowstone to escape the snow. The animals that were struck were likely from this herd.

Police did not say whether the driver of the semitruck broke any laws during the incident. In their statement, they reminded drivers to travel slower than the posted speed limit during winter conditions.

“Although speed many not necessarily have been a factor in this accident, road conditions at the time would dictate traveling below the posted speed limit,” the statement said. “Please do not drive faster than you can stop within the distance that your headlights project.”

The incident caused some confusion with authorities. An initial report suggested that two other vehicles were involved in the bison deaths. But the statement clarified that the semitruck was the only vehicle to have struck the animals.

“All of the bison were hit by the semi, and the other two vehicles were secondary incidents,” the statement said.