Some 8,000 lions bred for the sole purpose of being hunted are kept on game ranches in South Africa. Every year thousands of hunters—mostly Americans—pay handsomely to kill these lions within the confines of walls and fences, a practice known as canned lion hunting.

But starting today they’ll no longer be allowed to bring back the heads, skins, claws, teeth, and other lion parts from those kills. On Thursday, the U.S. Fish and Wildlife Service announced a ban on the import of trophies taken from captive-bred lions in South Africa.

Conservationists, animal welfare advocates, and even many hunters are cheering the decision.

“This is huge,” says Ian Michler, a conservationist and the narrator of Blood Lions, a documentary released last year that exposed