5 Shocking Animal Attacks on Tape Aug. 17, 2012 - What happens when the world's top predator decides to go off behavior? It can get ugly real quick. That was Dr. Jeff Ventre in an interview with "20/20." He was describing killer whales, which he trained for three years at SeaWorld, but his point -- captivity breeds aggression -- applies to many species, in water and on land. And trainers aren't the only victims. Zoos, which we think of as places for innocent family fun, have seen their share of ugly attacks -- many caused by humans going "off behavior." Click through to see five attacks caught on video. Watch the full story -- and see more amazing animal footage -- on "20/20: When Animals Strike Back" NOW An Effective Demonstration Alligator trainer Daniel Beck was trying to show an Ohio county fair audience how quickly gators react once they detect something inside their open jaws -- when the gator clamped down on his arm. The animal didn't release it for 21 seconds. Bert Lucas, producer of "The Kachunga and the Alligator Show," rushed in to keep the gator from flipping over into what's called a death roll. There's no nerve damage, there was no muscle damage. Everything's working, I just got a few stitches," Beck said. Up Close and Personal in Alaska In July 1994, a 29-year-old Australian tourist named Kathryn Warburton climbed a fence and railing to get close-up pictures of a polar bear named Binky at the Anchorage Zoo. Binky attacked. Warburton survived with a broken leg and bite wounds. Binky's teeth narrowly missed her femoral artery. The Anchorage Daily News later reported that Warburton blamed herself. It quoted her as saying, "It was the dumbest thing I've ever done." Feeding Time at the Berlin Zoo On April 13, 2009, a woman jumped a fence at the Berlin Zoo, entering the polar bear enclosure during feeding time. After thrashing in the enclosure's moat with a bear biting her back, the woman was pulled to safety and treated for severe injuries. Police did not know why the woman jumped the fence into the enclosure, but they did issue her a citation for trespassing. Tame This In October 2010 lions attacked a tamer during a performance at a circus in Lviv, Ukraine -- known as the City of Lions. The tamer was taken to the hospital, where he underwent surgery. Dunked by a Whale It was a harrowing scene at Sea World in San Antonio, Texas in 2004 when a killer whale turned on trainer Steve Aibel. Aibel survived the attack. "The best words that I can use are he lost a little bit of his focus," Aibel told reporters in 2004. I know (the whale) very, very well and I've never seen this before with this animal.