herd. reporter: local trackers pick up the rhino s footsteps and walk deeper into the brush. this is the angry one that already killed another one so he s likely just going to get up and come so we need to be ready. reporter: silence is crucial. trackers direct knowlton and his hunting guide with hand signals. we get closer and in an instant, the rhino flashes before us. the rhino moves around us but he s invisible. silent. a nearly 3,000-pound beast that can move like a ghost in the brush until it decides to charge. we don t see him until he s 30 feet away. charge right at us. i have to dive below knowlton s high powered rifle. a short while later, the rhino