Senators John McCain and Jeff Flake are pushing a proposal that would allow authorized hunters in the Grand Canyon to keep meat from the bison they kill. The senators say this will help manage the park’s herd.

These are no “ordinary” bison said McCain, but cattle-buffalo hybrids. He said the animals, known as beefalo, have proved devastating to vegetation at the Grand Canyon National Park.

Hunting is prohibited in at the park, but the National Park Service has the authority to kill animals in order to the protect resources.

The Grand Canyon Bison Management Act says the current herd of about 600 needs to be culled by a third.