A group of safari hunters has sued Delta Air Lines over its ban on transporting exotic animal bodies or body parts, known by hunters as “trophies.”

But an animal law expert who led a petition calling for the ban said the Atlanta airline deserves praise and should stick with the policy.

The Dallas Safari Club and one of its members, hunter Corey Knowlton, joined other hunting groups in suing Delta last week, arguing that the airline is “vilifying [U.S. tourist safari hunters] by refusing to transport the fruits of the hunt,” including elephants, rhinos, lions, leopards and buffalo.

The lawsuit, filed in Texas, alleges: “Not only is Delta’s embargo unconscionable — it is illegal” because the airline “is failing to fulfill its obligations as a common carrier” and the ban discriminates against hunters. A number of safaris were cancelled, said John Jackson, president of Conservation Force, a plaintiff in the lawsuit.

Delta declined to comment.

Earlier this year, Delta said it would ban shipment of certain animal trophies as freight. That came shortly after the outcry over the killing of a lion known as Cecil by an American hunter.

Chris Green, a Delta frequent flier who filed a Change.org petition asking Delta to stop shipping trophies, said in a letter on the website that public response to the hunters’ lawsuit “will confirm to Delta Air Lines that it did exactly the right thing…” The post quickly generated hundreds of comments supporting Delta’s stance.

Since the petition drive Green has become executive director of the animal law and policy program at Harvard Law School.

Corey Knowlton, the hunters’ lawsuit says, paid $350,000 to legally hunt a black rhino in Namibia, but was unable to ship the rhino back to the United States on Delta and “had to use a different carrier.”

Delta’s embargo appears to be “motivated by a desire to placate a noisy and ill-advised group of Facebook posters,” according to the lawsuit. The suit also contends that Delta’s ban jeopardizes the conservation benefits of tourist hunting.