Yellowstone National Park bison
Poor little bison calf: Not home, home on the range. Photo courtesy of Karen Richardson via Facebook

A father and son tourist loaded up a baby bison in their SUV at Yellowstone National Park, believing that he was cold and in need of being rescued. The incensed pair drove immediately to a park ranger station and "were demanding to speak with a ranger," witness Karen Richardson told "They were seriously worried that the calf was freezing and dying."

Rob Heusevelet, a father at the ranger station supervising a school field trip along with Richardson, told the men to remove the bison from their car and warned they could be in trouble for having picked up the animal.

"They didn't care," Heusevelet said. "They sincerely thought they were doing a service and helping that calf by trying to save it from the cold."

Park law enforcement was called and the two were given a ticket and a fine, plus ordered to show rangers the exact spot where they had confiscated the calf.

The confused animal was released, unharmed, at the spot where he had been picked up. Park rules mandate that visitors stay at least 25 yards (22.9m) away from any animal.

Bison — including calves — have a thick coat of fur and underfur with tough skin that makes it possible for them to tolerate the cold winters of the Yellowstone Plains. The bison was recently named the official national mammal of the US by President Obama.

Efforts are underway to help spread the population of the animals. Descendants of US buffalo purchased by Canada 140 years ago are being returned to an American Indian reservation in Montana, as part of an attempt to revive the population of the animals that once filled the Western plains.

As for the bison calf, when Richardson returned home she posted on Facebook a photo she had taken of the calf inside the SUV during her witnessing of the event, with the message: "Dear Tourists: The bison calf is not cold and it is not lost. Put it back!"