Rage of the Rhino (Mission Survival #7) by Bear Grylls

Young adventurer Beck Granger is invited to South Africa by an old friend of his parents' to help out on a project to prevent rhino poaching. But when he arrives all is not as it seems, and Beck is caught up in something more dangerous than anything he's ever survived before . . .

Not only are there the poachers to contend with, but somebody seems desperate to track Beck down - whatever the cost. And then there are the hundreds of wild animals . . .