captured on tape and happening, believe it or not, at a circus. stunning video from cnn and i-reporter doug shepherd showing a lion mauling his trainer, and this is far from the only incident like this one. cnn s brian todd has been looking into the attacks for us. brian? wolf, we will show you a classic predator and take look at this guy, a 5-year-old fully mature male lion from south africa sitting in his front yard at the national zoo. we are looking at the animal s behavior not only under normal circumstances burk when they are irritated. reporter: in an instant a massive lion turns on the trainer, and this ferocious attack happened on a family in ukraine last weekend. as one lion strike, another joins in, and biting the trainer s left arm. as people in the crowd scream, workers hose them down the try to keep them at bay, but seconds later, another strike.