A spokesman for the Aspinall Foundation warned that poachers could be planning to hunt down the 20 rare black rhinos that live at the foundation's two reserves near Canterbury.
Parks manager Bob O'Connor said it was impossible to say how serious the threat is, but the parks have increased night-time patrols "and we are asking local people to work with our staff to increase the number of patrols."
O'Connor told the BBC Kent police relayed a warning from a tipster that poachers had their eye on the rhino horns, which are used in Asian traditional medicine and can fetch a high price.
"Over the last few years there has been a trend for breaking into museums and stealing stuffed rhino heads for their horns, including one recently in Kent," he said.
Benedict Cumberbatch's dramatic reading of R. Kelly lyrics is just what you need
Kate Middleton recycles dress at movie premiere