The tranquilizers can help prevent the animals from suffering stress-induced heart attacks or even injuring themselves, he said. They also help to safeguard vets and others who must work with the animals until the marine mammals are well enough for release.
"We do not use benzodiazepines over long periods of time," Johnson said, mentioning that the drugs can be addictive. "Dose ranges vary, depending on the species."
SeaWorld's Ikaika, unlike rescued animals, was born in captivity at the theme park. Jared Goodman, director of animal law at PETA Foundation, told Discovery News that diazepam was given to this orca and the others at SeaWorld "as a result of aggression due to a seriously unnatural grouping of orcas."
He explained that Ikaika was attempting to breed with his half-sister (Nalani, "who is the first inbred orca at SeaWorld," he said) when Nalani "was only days old." He added that the mother of both, named Katina, gave birth to Nalani after breeding with Taku -- her own son -- at the park.
Goodman contends that Animal Welfare Act guidelines concerning captive marine mammals are "very minimal and are not sufficiently enforced," and that marine mammals should not be kept in captivity "just for our entertainment."
At least it appears that benzodiazepine drugs are no longer being given to Ikaika, now at SeaWorld in San Diego, to prevent aggression. David Koontz told Discovery News that "none of the killer whales (orcas) at SeaWorld San Diego are on these medications."