The number of rhinos poached in South Africa has soared in the past five years, from 13 killed in 2007 to more than 630 in 2012. The prehistoric, battleship-gray animals are often found on their knees, bleeding to death from a gaping stump on their face.

“Ever seen a dead rhino?” asked Philip Jonker, who works for a private security firm that has gone into wildlife protection. “It’s worse than going to a funeral.”

The only answer, some contend, is to legalize the trade, which would flood the market with rhino horns, lower the price and dissuade rhino poachers from risking their lives — or so the argument goes. Rhino horns regenerate, and the horns can be shaved down every few years and sold off without significantly hurting the animal.

One of most passionate advocates of this legalization movement is John Hume, a South African entrepreneur who now owns more than 800 rhinos, with names like Curly, Titan, Hillary and Pinocchio, and has amassed a 2,000-pound mountain of horn worth millions of dollars — if he is ever allowed to sell it.

“Why shouldn’t the person who breeds rhino get a reward?” he asks.

Every time Mr. Hume’s ranch hands trim down a few rhinos, they organize an armed escort to take the horns straight to a safe-deposit box in a bank because the same gangs that waylay armored bank trucks are now cruising around South Africa looking for rhino horns.

But many wildlife groups say legalizing the rhino trade would be a disaster.

“The consuming power in my country is growing so rapidly that the supply would never meet the needs,” said Jeff He, spokesman for the Chinese branch of the International Fund for Animal Welfare. “And besides, it’ll always be cheaper to poach an animal than raise it.”

Image Many rhinos are being poached in Kruger National Park, a vast wildlife refuge. Credit... The New York Times

Kruger National Park, an enormous wildlife refuge in South Africa’s northeast, is where many rhinos are being poached. The park lies on the border with Mozambique, a much poorer country still scarred from years of civil war. Park rangers say Mozambican gunmen are pouring through Kruger’s chain link fences, downing rhinos left and right.