Infections, like the one Tilikum is reportedly suffering from, are also more common in captive orcas than wild ones due to the stress of captivity and poor water quality.
But SeaWorld's kept a tight hold on Tilikum, who's at the center of their artificial insemination program; he's fathered 21 of SeaWorld's captive-born calves, only half of whom are still alive.
Hopefully Tilikum will pull through - but it's doubtful SeaWorld would have released this information if a recovery were in sight.
Tilikum's illness is just the latest in a streak of bad news when it comes to SeaWorld's animal health. Five marine mammals have died at the parks since last summer, including Unna, Tilikum's daughter, who passed away at just 18 from a reported fungal infection.