Recently-publicized documents showed that theme park SeaWorld has been treating its orca, or killer whales, with benzodiazepines. This revelation comes on the heels of heavy criticism against SeaWorld from animal rights activists regarding the theme park’s treatment of killer whales.

A sworn affidavit, filed in the Ontario Superior Court of Justice during a dispute between SeaWorld and Marineland over transportation details of killer whale Ikaika, outlines how SeaWorld had been giving its animals benzodiazepines, the class of drugs that includes Xanax and Valium. SeaWorld’s critics, who still have plenty of steam from the documentary Blackfish, believe that the whale’s mental issues are directly related to their captivity.

“The veterinary records show that orcas at SeaWorld are given psychotropic drugs to stop them from acting aggressively towards each other in the stressful, frustrating conditions in which they’re confined instead of funding the development of coastal sanctuaries – the only humane solution,” said Jared Goodman, Director of Animal Law at the People for the Ethical Treatment of Animals (PETA).

Blackfish revealed the story of SeaWorld’s orca Tilikum. The whale has been accused of killing three people, but SeaWorld still houses Tilikum. Critics and activists further attribute this violent behavior to the killer whale’s constant state of captivity and imprisonment.

“They do not cope with being kept in these tanks,” said Orca Research Trust founder Ingrid Visser. “They survive to some degree, but they don’t thrive to any degree. They show stereotypical behaviors that are abnormal, repetitive behaviors like head bobbing, chewing on concrete, and self-mutilation by banging the side of their heads on the side of the tank, and there isn’t a single living orca in captivity where you cannot see one of these behaviors, and in many of them you see multiple examples of these behaviors.”

According to animal rights advocacy blog, The Dodo, SeaWorld has been targeted in the past for administering such medications to mother and child orca whales to dull the effect of separation anxiety experienced between the two. But SeaWorld officials defend the use of benzodiazepines on its captive animals.

“These medications can be used for sedation for medical procedures, premedication prior to general anesthesia, and for the control of seizures,” said SeaWorld spokesman Fred Jacobs. “There is no higher priority for SeaWorld than the health and well-being of the animals in its care.”

However, activists and researchers contend that the drugs are most likely used to treat anxiety and hyper-aggression exhibited by the whales as a result of prolonged captivity from the wild.

Josh is a writer and researcher with Ring of Fire. Follow him on Twitter @dnJdeli.