BOZEMAN, Mont. (AP) — State wildlife officials aren't sure what killed three bison that were found dead in the Yellowstone River, but they know it wasn't a virus spread by domestic sheep.
The Department of Fish, Wildlife and Parks announced Tuesday that tests on two more bison turned up negative for malignant catarrhal fever. The first negative test was announced late last month.
FWP veterinarian Jennifer Ramsey says all three animals found in mid-May showed signs of physical trauma. Two had fractured pelvises and one had crushed ribs. Ramsey says the injuries could have occurred if the animals were swept away when the river was swollen with spring runoff.
The bison were tested out of concern they may have been sickened by a virus after a rancher introduced about 30 domestic sheep to property that borders the Yellowstone River near Gardiner.