South Africa says at least 588 rhinos have been killed by poachers this year alone, the worst recorded year in decades.
The nation's Department of Environmental Affairs says most of the killings occur in South Africa's Kruger National Park, a region of about 19,400 square kilometers in the country's northeast.
From the 1990s to 2007, rhino killings in South Africa by poachers averaged about 15 a year. However, the number has soared as buyers in Asia pay the United States street value of cocaine for rhino horn.
Rhino horn is made of keratin, a tough protein found in human fingernails. There's a belief in Asia that taking ground-up horn cures diseases. However, no medical evidence supports that.