Corey Knowlton thinks black rhinos are some of the most amazing creatures on the planet. It is easy to see why. These huge animals can weigh well over a tonne, with hide as tough as leather. At charging speed, a black rhino can reach 34 miles per hour - fast enough to make sprinter Usain Bolt look like a dawdling amateur. And yet, the black rhino is extremely rare. Setting eyes on one of the five thousand that survive in the wild is a rare privilege.

That is what Corey Knowlton wants to do. 'I want to experience a black rhino,' he told a local news team. 'I want to be intimately involved with a black rhino.' He left out the last part. After finding and 'experiencing' his rhino, Corey Knowlton will line up a high-powered rifle and shoot the animal dead.

Knowlton paid $350,000 (212,000) for one of a handful of licences issued each year by the government of Namibia. Each licence entitles a hunter to track down and kill a black rhino.

Now he is paying another price. Animal lovers around the world have whipped up a storm of outrage against Knowlton. Some have even threatened his life, promising to do to him and his family what he wanted to do to the black rhino.

But not all conservationists oppose the planned rhino hunt. In fact, some think hunting the black rhino is actually a very good idea.

Why? Because protecting rhinoceroses costs money. The biggest threat to black rhinos comes from poachersRhino horns are worth more per kilogramme than gold. A single rhino might have horns worth 100,000. In economically distressed areas of southern Africa, that is a serious incentive to hunt the animals down. The horns are then cut off and smuggled to South East Asia, where they are used in traditional remedies and as status symbols. who hunt them for their horns. Defending rhinos against poachers means employing armed guards in nature reserves and enlisting the support of local people in keeping poachers out. Corey Knowlton's $350,000 comes at the cost of one rhino's life, but will go a long way towards keeping the remaining rhinos safe and well.

Anyway, the rhinos that are targeted by hunters are older males who contribute little to the survival of the herd. In fact, older rhino males have been seen fighting and killing other males and even sometimes females and their young. The evidence is that killing a few older males leads to more rhinos surviving in the wild, not fewer.

The argument is not fully settled, but it looks as though hunting a few black rhinos actually helps preserve the species as a whole. If that is the case, say many conservationists, surely Corey Knowlton's hunt is justified. He is doing more to help rhinos than most people ever do.

But most of the people protesting against his 'licence to kill' will not be convinced. You wouldn't kill one innocent human to save five more. In the same way, killing innocent rhinos for pleasure is always wrong, regardless of the wider consequences.