Rangers in a major South African wildlife park recently darted a rhino to install a tracking device on the threatened animal as part of efforts to stop poaching.

Journalists witnessed the operation in Kruger National Park, where poachers have killed rhinos in record numbers to meet consumer demand for their horns in parts of Asia, particularly Vietnam.

Markus Hofmeyr, a senior veterinarian for South Africa's national parks service, says the tracking device will allow rangers to monitor the movement patterns of rhinos and develop better ways to protect them.

He requested that media not report any detail about the tracking device because poachers are on the lookout for any information that could help their crimes.