Yellowstone National Park rangers tried to reunite a newborn bison calf with its herd after a tourist took the baby bison from the wild and placed it in a SUV last week.
Attempts to return the calf to its herd were unsuccessful and the calf was euthanized, according to a National Park Service statement.
A father and son were cited for transporting the calf to a park facility. The park service said the tourists had "misplaced concern for the animal's welfare."
Teacher Karen Richardson, of Victor, Idaho, was chaperoning a fifth-grade field trip to the park in Montana last Monday when she saw the two foreign tourists pull up to the ranger station with the calf. Richardson took a photo of the calf in the vehicle and heard the tourists tell the rangers they were worried the calf was too cold, she told NBC station KECI of Missoula, Montana.
The National Park Service warns that these interactions can endanger people and asks tourists to "respect wildlife."
Rangers took the animal back to where it was picked up, but they could not get it back with the herd after several tries.
"The bison calf was later euthanized because it was abandoned and causing a dangerous situation by continually approaching people and cars along the roadway," the park said in a statement.
Park regulations require people maintain at least 25 yard distance from all wildlife and at least 100 yards from bears and wolves.
In another recent high-profile case, a woman was seen on video trying to pet an adult bison as it rested on the boardwalk around Old Faithful. In another, tourists posed for photos dangerously close to bison that had caused a traffic jam on a road.
The Associated Press contributed to this report.