. >> reporter: following their every move, boone smith. >> they're going to make a go at the hippos here those lions locked on the hippos, it was lightning fast. >> reporter: we're here in south afri africa, to put himself squarely on their turf. man versus lion, capturing it all on camera. >> i wanted to be a member of the pride. see that point of view. i've been tracking three of them all morning. >> reporter: he makes his living tracking and trapping big cats all over the world. he's a throwback to a far more wild era. a fourth-generation tracker. he's tagged everything from cougars in idaho to snow leopards. >> there's an addiction to the adrenaline. the adventure, what's over the next hill, down the next valley. >> reporter: we set out with him to get a taste of that feeling. it's dawn, and it's very early. he gets to work, tracking the queen lioness. he knows she's had three new cubs, but no one has seen them. and ranger greg is with us, with a magnum just in case. >> we're going to go very slowly. >> reporter: but danger finds us fast. oh, my god, there's a rhino right there. a ra