On a shoe he made last year, a spike juts from the top of the foot like a rhinoceros horn.

NEWYORKER: Sole Mate

In China, there is a centuries-old traditional belief that drinking from the intricately carved rhinoceros horn cups brings good health.

WSJ: 3 charged in smuggling horns of endangered rhinos

Since 1976, trade in rhinoceros horn has been regulated under the Convention on International Trade in Endangered Species of Wild Fauna and Flora, a treaty signed by more than 175 countries to protect fish, wildlife and plants that are or may become imperiled as a result of demand in international markets.

WSJ: 3 charged in smuggling horns of endangered rhinos

To explain the pressures many endangered species face from humans, Attenborough came face-to-face with a baby rhinoceros in Kenya, whose horn had been removed to protect him from poachers.

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At the Metropolitan Police stores, Sergeant Knox shows me a horn from a black rhinoceros, brutally hacked away from the animal's head.

BBC: UK laws 'spurring trade in endangered species'