The day after that, the other one passed away.A nearby strike scrambles the animal's neurological system and heart. With bison, it's "hard to determine at any given time if they're sleeping or just laying there," he said.Bison often stay close together, he said.No one witnessed the lightning strike.The museum is now left with just one bison. The animals graze on the west side of the property, between Highway 281 and the administration building — not far from the earth lodge.The bison do not belong to the museum. And bison are a similar size.The museum wrote about the bison deaths on social media. "And the community is very concerned," Hochstetler said.In that posting, the museum wrote, "This loss is deeply felt by our staff and community, and serves as a somber reminder of the power of Mother Nature.