A Delta Airlines Boeing 757 takes off in Tampa, Fla. (AP Photo/Chris O’Meara, 2011 file)

A Delta Airlines Boeing 757 takes off in Tampa, Fla. (AP Photo/Chris O’Meara, 2011 file)

In August, shortly after a dentist from Bloomington killed a lion named Cecil in Zimbabwe, Delta Air Lines joined a growing list of carriers that had decided not to transport game-hunting “trophies.”

In a brief statement issued Aug. 3, the Atlanta-based carrier said that “effective immediately, Delta, the primary carrier serving the Minneapolis-St. Paul International Airport, will officially ban shipment of all lion, leopard, elephant, rhinoceros and buffalo trophies worldwide as freight.”

That decision, and similar ones by other airlines, made close to 400,000 petition-signers extremely happy, but angered conservation-hunting groups who maintain it’s necessary to kill a few animals to save a population.

Count the Dallas Safari Club among those organizations so upset that on Thursday they sued Delta in Dallas federal court, insisting that a ban on the shipping of game trophies will, among other things, harm their conservation efforts and punish villages relying on tourist revenue. They also claim the ban discriminates against well-meaning hunters and “an unpopular but non-hazardous type of cargo,” and that “not only is Delta’s embargo unconscionable — it is illegal.”

Also named as a plaintiff is Dallas resident Corey Knowlton, the man who paid the safari club $350,000 for a trip to Namibia and a permit to kill an endangered black rhino.

Says the suit: Knowlton “has hunted all the Big Five and, in May 2015 hunted a black rhino in Namibia. To participate in this hunt, Mr. Knowlton contributed $350,000 to Namibia’s Game Products Trust Fund, to be used exclusively for black rhino protection and recovery. Namibia’s Ministry of Environment and Tourism would not use these funds until Mr. Knowlton’s trophy was imported into the U.S. Delta unlawfully refused Mr. Knowlton’s request to ship the trophy from Southern Africa, further delaying the import and the Ministry’s expenditure of these much-needed conservation funds.”

National Public Radio reported this year that the handful of permits issued annually by Namibia’s Ministry of Environment and Tourism are intended to remove from the population “older rhinos that are no longer able to breed but still pose a deadly threat to younger male.” The money raised from the sale of the permits goes toward conservation and anti-poaching efforts.

Dallas Safari Club and the other plaintiffs — including Louisiana-based Conservation Force, the Houston Safari Club, Zimbabwe’s CAMPFIRE Association and the Tanzania Hunting Operators Association — claim the ban will cause a “catastrophic” chain reaction.

“Delta’s embargo threatens the tourist safari hunting industry’s entire user-pay, sustainable use-based conservation paradigm,” says the suit. “It would be catastrophic to people and wildlife to eliminate the most habitat, prey base, operating budget revenue, and community incentives. Wildlife numbers will plummet. But this will occur if Delta continues to discriminate against the cargo of U.S. hunters. Rather than celebrating the conservation contributions of U.S. tourist safari hunters, Delta is vilifying them by refusing to transport the fruits of the hunt: trophies of the prized Big Five (elephant, rhino, lion, leopard, and buffalo). Delta is treating these legally acquired trophies as if they were contraband.

“America’s business, professional, and civil leaders — many of whom are frequent fliers — should not be lumped with traffickers (unlawful trade). The stigma will understandably affect their willingness to hunt in Africa. Because it dissuades lawful hunters, Delta’s embargo jeopardizes the benefits of tourist hunting and its centrality in the conservation programs of African range states. And worse, the embargo deprives Big Five species of essential conservation funding and support.”

Delta did not respond Friday to a request for comment.