It was revealed Monday in an affidavit filed in a lawsuit between SeaWorld and Marineland that SeaWorld administered anti-anxiety drugs to its orca whales to keep them mentally stable in captivity.

A closer look at the documents reveals that two male whales -- Ikaika and Taku -- were acting aggressively toward a young calf, and one was even trying to breed with her. Three whales -- Taku, Ikaika and Tina, the calf’s mother -- were all given diazepam, a drug first marketed as Valium that is used to treat anxiety, panic attacks, insomnia and seizures. The document reads:

In an email to The Dodo, Naomi Rose, marine mammal scientist at the Animal Welfare Institute, wrote that aggressive behavior like that exhibited by Ikaika and Taku is not common in the wild.

Aggression among orcas in the wild is rare in some populations, more frequent in other populations, but in all populations, it rarely escalates to injurious (beyond rake marks on the skin) because the animals can escape each other in three dimension (up, down, and sideways).

She also noted that the sexual behavior by Ikaika (who was born in 2002) toward a calf is not normal, either.

“These are highly family-oriented mammals, where all family members help raise the matriarch’s offspring,” she said. “The idea of a calf being targeted for sexual interactions by other whales is grotesque.”

PETA asserts that using psychoactive drugs on orcas is not a new technique for the park. Spokesperson Jordan Uhl says:

“While there’s no further documentation readily available given the limited records that have been made public, this small glimpse into the company's vet records, as well as SeaWorld’s own acknowledgement of administering drugs, indicates that this is a common and widespread practice.”

SeaWorld, meanwhile, maintained in a statement issued after the earlier report that its use of such drugs “is limited, infrequent, and only as clinically indicated based on the assessment of the attending veterinarian. There is no higher priority for SeaWorld than the health and well-being of the animals in its care.”