Sea World tragedy: How common are 'killer whale' attacks?

Tilikum, the killer whale that drowned a trainer at Sea World in Orlando, Fla., Wednesday has been involved in three human fatalities. The orca, who was originally captured in the wild, may have been under high levels of stress.

Tilikum, the "killer whale" that drowned veteran trainer Dawn Brancheau at Sea World theme park in Orlando, Fla., Wednesday, has a particularly aggressive track record, say experts.

“It sounds like he was a different killer whale,” says Nancy Black, lead marine biologist at California’s Monterey Bay Whale Watch. “They were always a little bit leery about him because of previous incidents.”

Wednesday’s incident is the third time Tilikum, a 12,300-lb. orca, has been involved in a human fatality. In 1991, a trainer died after falling into a tank with Tilikum and two other whales at Sealand of the Pacific, a theme park in Canada. In 1999, a homeless man sneaked into the whale tank at Sea World in Orlando after hours. The man died of hypothermia, although bruises and bite marks suggest that the orca may have had a role in his death.

Tilikum is the father of the orca, Ky, who also tried to drown his trainer at a Sea World park in San Antonio, Texas.

Experts say several factors may have played a role in Tilikum’s behavior Wednesday.

As a wild orca kept in captivity, Tilikum may have been under unusually high stress. He was captured near Iceland in November 1983, according to Discovery News, and kept in small tanks for most of his life.

“I’m sure it was a high stress situation,” says Ms. Black. “Being kept in a small tank like that, especially because he was originally from the wild. I’m sure he had a hard life, kept in a holding pen, not getting a lot of exercise.”

Tilikum was a “stud,” used in Sea World’s breeding program since 1992. His frequent breeding – he has sired at least 17 calves – and high hormone levels may have also contributed to his aggressive behavior.

Black says killer whales can enter “different energy levels” when hunting, socializing, or mating, making them more prone to aggressive play and attacks.

“He’s more excitable. Maybe he was stressed out, maybe he had frustration,” she says. “So he grabbed the closest thing to him to take out his frustration and high energy level.”

Orcas in captivity are typically fed 140 to 240 pounds of food per day, according to the Orlando Sentinel, so it’s unlikely Tilikum viewed his trainer as prey. Orcas in the wild do not target humans, adds Black, noting that there are no documented cases of killer whales attacking humans in the wild.

“In the wild, it doesn’t happen, but … in captivity, you hear every once in a while of something like this happening,” she says. “I don’t think he planned to kill her. He grabbed her, and the accident happened.”

Accident or not, it’s not unusual behavior for a predatory animal whose very nickname suggests it kills, says Richard Ellis, a marine conservationist at the American Museum of Natural History in New York.

“When you’ve got a big predatory animal near warm-blooded prey, the possibility of attack is very high,” Mr. Ellis says.

Add to that the fact that Tilikum was a wild animal kept in captivity working to entertain tourists under potentially stressful conditions, and an incident like Wednesday’s isn’t so surprising, say Ellis and Black. And, they add, it’s evidence that orcas shouldn’t be held in captivity for human entertainment.

“These animals are too big for tanks,” says Black. “They’re wild, intelligent animals with a big social structure. They’re really not an appropriate animal to keep in captivity.” (See the Monitor's story on why animal rights groups say large marine mammals don't belong in theme parks, here.)

Ellis agrees, but says he doesn’t expect to see any changes soon.

“It’s an unfortunate way to experience nature: to see animals turned into Disneyland animatronic puppets for the entertainment of people,” he says. “I would rather they weren’t, but this is where we are in entertainment and education right now, so I don’t think this is the end of it.”