Baby bison euthanised after couple attempt 'rescue'

The bison calf was strapped in and taken for a ride (Karen Olsen Richardson / Facebook)
The bison calf was strapped in and taken for a ride (Karen Olsen Richardson / Facebook)

"Misplaced concern" one couple had for a baby bison in a United States national park ultimately led to its death after it was rejected by its mother and herd.

Last week, two tourists saw the calf in Yellowstone National Park and, thinking it was cold, strapped it into the back of their vehicle and drove it to a nearby park facility concerned for its welfare.

The park is now warning people about getting too close to wildlife in the park -- which also includes bears, wolves, badgers, cougars and coyotes -- because it is "inappropriate, dangerous and illegal".

A spokesperson for the park says what the pair had done was dangerous because adult animals are very protective of their young and can get aggressive trying to defend them.

It could also mean the young can be rejected by their mother.

"In this case, park rangers tried repeatedly to reunite the newborn bison calf with the herd. These efforts failed.

"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 spokesperson says.

It's not the first time visitors to the park have got up close and personal with bison.

A recent viral video showed a man getting within arm's length of an adult bison, and another showed someone taking photos at "extremely unsafe and illegal distances".

Five people were seriously injured by bison last year when they got too close.

The park's rules mean people need to stay at least 23 metres away from all wildlife. That increases to 91 metres when it comes to bears and wolves.