Shamu Rocks, at Orlando SeaWorldcourtesy of Miss Quarel.

The horrific killing trainer Dawn Brancheau at Sea World by the orca Tilikum, or Tilly, prompted Sea World to indefinitely close its killer whale shows. But the Tilly problem is a long-term one. He fathered 10 of the current 42 other captive orcas around the world–nearly one-quarter of the stock.

Many blame the attack on the whole practice of holding these huge, sociable whales captive to entertain us. Jennifer Viegas at Discovery reports that Tilly, a stud whale, may have had high testosterone levels or swings. That’s what made him the most successful male killer whale captive breeder, siring a record 17 calves, 10 of which are still alive, Viegas says. His offspring include Unna, Sumar, Tuar, Tekoa, Nakai,, Kohana, Ikaika , Skyla,  Malia and Ky, who attacked a trainer in San Antonio in 2004. Plus, he has at least one grandchild.

That means nearly one-quarter of the killer whales held in captivity around the world and nearly half the 22 held by SeaWorld are related to a killer whale with high testosterone and high aggression. Even if he weren’t a flawed individual, that’s a terribly inbred population. But now that he’s been very publicly involved in three attacks on people, it highlights how misguided these breeding programs might be. Would you keep breeding the dog that attacks and kills people? 

But breeders probably had little choice but to rely on Tilly. No other male was anywhere near that

Keep reading Killer Whale Tilly Father to One-Quarter Captive Orcas