What Caused a Killer Whale to Attack?

SeaWorld Trainer Attacked, Killed By Whale

Trainer Dawn Brancheau understood the power of SeaWorld's biggest killer whale better than most. She worked with Tilikum for more than 10 years. Yet on Wednesday, as she stood knee deep in water rubbing the massive animal's head as a reward for a good training session, he turned on her.

"She was leaning over his head and she had a ponytail and that ponytail he probably sensed it against his face and he grabbed it," said SeaWorld curator Chuck Tompkins.

And he wouldn't let go. Trainers had to coax the killer whale into this medical pool nearly a football field's length from where the attack happened, and lift him from the water to pry her free. An autopsy showed Brancheau died from "multiple traumatic injuries and drowning," reports CBS News correspondent Kelly Cobiella.

A brutal end for a woman who had a passion for killer whales. Brancheau grew up in landlocked Indiana, and discovered killer whales on a family vacation to SeaWorld when she was 9 years old.

"Right there she said this is what I want to do," said Diane Gross, Brancheau's sister.

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She became one of a dozen trainers qualified to work with the 12,000 pound Tilikum, the largest orca in captivity, and the only one linked to two previous human deaths in 1991 in Canada and again in 1999 at SeaWorld Orlando. SeaWorld staff knew he was potentially dangerous and they treated him that way - no trainers were allowed to swim with him.

Cobiella spoke with a former SeaWorld contractor who has watched Tilikum for 10 years. He didn't want to be identified because he plans to work for the company again. He says despite Tilikum's violent past he never saw more than temper tantrums.

"His personality is very laid back," he said. "I've seen him bang his head on the glass. I want to say that Tilikum wasn't doing this intentionally but unfortunately it just looks like he either got curious or bored and wanted to grab her."

He says the 22-foot-long killer whale spends a lot of time alone often in a 15 foot deep pool because he's used for breeding, which is not natural for such a social animal, marine experts say.

"It's a part of their lives to have whales visible to them at all times," said Richard Ellis, a marine conservationist at the American Museum of Natural History. "Put one in a tank and that whale is unhappy."

The lead trainer here says the animal will not be kept away from other killer whales. Tilikum is a valuable asset, he's fathered 15 calves and SeaWorld will continue to breed him.