A black rhinoceros in Etosha National Park in Namibia. (Barbara Scheer/dpa/Picture-Alliance GmbH/AP)

Ben Carter heard the story of the fearsome black rhinoceros during a trip to Namibia more than a year ago, and it’s still fresh in his mind.

The bull roamed the dry fields around a sprawling ranch where Carter had stayed as a guest. It was a brute, weighing nearly 3,000 pounds. It was said to be too old to sire offspring but jealously guarded cows in the herd, preventing them from breeding with younger males.

“He’s killed a couple of calves, a couple of cows and a breeding bull,” said Carter, executive director of the Dallas Safari Club, a group that advocates wildlife conservation through hunting. “He’s not contributing to the habitat; he’s just existing there.”

Carter never saw the bull, but like the rancher who told him the story, he felt that the rhino had to go for the sake of the herd. Carter took the added step of asking the Namibia Ministry of Environment and Tourism in Windhoek to give his club permission to auction one of five permits the ministry issues each year to hunt problem rhinos.

That auction — held in Dallas last January, at a time when a wave of poaching had dramatically reduced Africa’s black rhinoceros population — was a public-relations disaster.

Weak enforcement and light penalties encourage smugglers to traffick in rhino horn and elephant ivory, which is pushing several large mammals toward extinction.

News outlets chronicled a battle that pitted hunters who say shooting problem rhinos allows the population to flourish against animal lovers who say killing any of the endangered animals for sport should not be encouraged. They say a problem rhino should be relocated, not shot.

The vitriol boiled over shortly after the auction, when a hunter who submitted the winning bid of $350,000 said he received death threats. “It has been a nightmare,” said Corey Knowlton, a consultant to a hunting association in Virginia who has hunted big game around the world.

Now the U.S. Fish and Wildlife Service is smack in the middle of the mess.

The agency is to decide this month whether to grant Knowlton a permit to import the animal’s remains into the United States as a trophy after he kills it.

As part of an international treaty to protect endangered animals, the United States pays close attention to Americans who hunt overseas and has considered Knowlton’s request for months. It is not a simple decision.

Black rhinos numbered 70,000 at the start of the 1960s, before a wave of hunting and poaching occurred. An international crackdown stopped poaching for a while, but it resumed several years ago when black-market prices for rhino horn in China and Vietnam, where it is valued as ornaments and traditional medicine, reached $45,000 per pound.

Fewer than 5,000 of the animals remain.

Protesters picket outside the Dallas Convention Center, where the Dallas Safari Club held a show and auction in January 2014. The club auctioned a permit to hunt an endangered black rhinoceros in Namibia. (Tony Gutierrez/AP)

Usually, the Fish and Wildlife Service receives three to eight public comments on applications for permits to import hunting trophies. But Knowlton’s application, along with that of a second rhino hunter — Michael Luzich, a Las Vegas investor who negotiated separately with the Namibian government for a permit — generated 15,000 e-mails and 135,000 signatures on a petition.

That number is “unusually high,” said Danielle Kessler, a specialist for the agency’s International Affairs program. The volume and nature of the public reaction is partly why a decision is not expected until the middle or end of January.

Knowlton said in a telephone interview Tuesday that he’s confident that Fish and Wildlife will grant him a permit to import the trophy, and he’s not sure what he’ll do if the agency does not. Namibia’s hunting season starts in February.

“There’s a group of rhinos that they want killed,” Knowlton said of Namibia. “Since this permit was approved, a number of rhinos have been killed by other rhinos. Also, poaching has taken place.”

But why import its head for a trophy? “It’s hard to say why hunters value the remains so much — respect, a memorial, the time you had with it, I believe it’s all of that,” Knowlton said. “A hunter’s relationship with wildlife is intimate.”

Jeff Flocken, a regional director at the International Fund for Animal Welfare, disagreed. He described Knowlton as one of “a dwindling population of Americans who get off on killing rare animals.”

Flocken doesn’t think much of the Dallas Safari Club’s argument that eliminating sterile old bulls protects other rhinos. “The bottom line is they wanted an opportunity to kill rhinos,” he said.

But animal rights groups may be fighting a losing battle. While they argue that the lives of belligerent older rhinos should be spared, they are not willing to meet the estimated $10,000 cost of moving each problem animal by helicopter, and Namibia says it cannot pay that cost.

And a powerful conservation organization that catalogues the world’s wildlife in a bid to protect them, and determines whether each species is threatened or endangered, is on the side of Namibia and the hunters.

In a statement, the International Union for the Conservation of Nature said the concern over killing a rhinoceros for sport is understandable but confuses illegal poaching with well-managed hunting tourism.

“Well-managed trophy hunting has little to do with poaching, and indeed can be a key tool to help combat it,” the union said. Without it, African conservationists “would not be able to employ the upwards of 3,000 field rangers employed to protect wildlife and enforce regulations.”

On top of that, Namibia’s conservation is viewed by Fish and Wildlife as one of most responsible programs in Africa. Knowlton said he was encouraged by at least one member of the conservation union to attend the auction and support Namibia.

In 2013, Fish and Wildlife Director Daniel M. Ashe said it is wise to put down old rhinoceros bulls for conservation. And last year, Fish and Wildlife approved the first permit to import a rhino horn trophy in more than three decades without a single opposing comment, according to a statement on the agency’s Web site.

“I’m not buying it,” Flocken said. “With all due respect to Dan Ashe . . . no one knows when rhinos are no longer viable. I’ve yet to see a peer-reviewed paper that shows that’s true. The dominant male does keep the females from other males, but I would like to see research that shows a male is no longer viable.”

Flocken also scoffed at arguments supporting hunting tourism.

“Honestly, killing an old angry black rhino on a luxury safari is about as dangerous as me walking into my living room and shooting the couch,” he said.

A hunter, Robert Kern, called animal rights activists such as Flocken “the bunny-hugger contingent” — easily swept up by emotions.

Kern, president of the Hunting Consortium in Berryville, Va., where Knowlton acts as a consultant, said the safari club’s auction will benefit Namibia. So will the $200,000 that Luzich, the Las Vegas investor, paid directly to the Namibia Ministry of Environment and Tourism.

Carter said the furor over the auctioning of the hunting permit doomed his expectations for a bid topping $1 million. “We probably had four to five people who were willing to bid a substantial amount,” he said. “In the end, we only had three bidders. It was more risk than they were willing to take with their business.”

Knowlton said the anger shocked him, but he doesn’t regret participating. “This wasn’t my plan, but the plan of the Namibia Environment and Tourism,” he said. “They understand I wasn’t this evil guy who was hell-bent on killing something.”