A record number of rhinos were poached this year in South Africa, home to the greatest number of the animals, as rising demand in Asia for their horns led to increased killings of the threatened species.

At least 443 rhinos have been killed in South Africa in 2011, up from 333 last year, the national park service and conservationists said.

The street value of rhinoceros horns has soared to about $65,000 a kilogram, making it more expensive than gold, platinum and in many cases cocaine, as a belief – with no basis in science – has taken hold in recent years in parts of Asia that ingesting it can cure or prevent cancer.

South Africa, home to more than 20,000 rhinos, was losing about 15 animals a year a decade ago. But poaching increased dramatically from about 2007 as a growing affluent class in places such as Vietnam and Thailand began spending more on rhino horn for traditional medicine.