Truck collides with Yellowstone bison herd outside park, killing 13

Thirteen bison died Wednesday after a semi-truck slammed into a herd just outside Yellowstone National Park, authorities said. Some of the bison survived the collision but were later euthanized.

The West Yellowstone Police Department stated in a news release that the incident occurred after dusk on Highway 191 near mile-marker 4. It was unclear if the truck driver was injured.

Bison sightings are common on the route during the winter when paved or snow-plowed roads are an inviting means of travel for the colossal animals.

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

Highway 191 runs north to south, inside and outside of the park, before connecting to Highway 287 north of West Yellowstone. West Yellowstone is just outside the park's West Entrance.

More than 5,000 bison inhabit Yellowstone National Park and are not restricted by boundaries.

Police said it was unclear if speed was a factor in the collision, but requested that motorists drive slower than the posted speed limit when driving in wintry weather.

Bison are dark brown and difficult to spot on roadways in the dark. A handful of bison are struck each year by vehicles inside the park.