Another Netflix documentary, this one about Orcas (killer whales) and their unfortunate history of injuring or killing their trainers in whale parks. You put a 5-ton self-aware mammal in a small concrete holding pool and, yes, they can get a little aggressive. As the show notes, there is not a single documented case -- not a single one -- of an Orca attacking a human in the wild.
But at SeaWorld, where negative as well as positive reinforcement has been used, there have been several incidents of whales turning on their captors.
During the show Ken Balcomb, the Orca expert / champion who lives two houses down from my parents' house, is interviewed. At the end of the show several ex-trainers are shown on a whale-watching boat in the harbor of Friday Harbor, where my parents lived.
The stories told, and the video evidence shown, make it clear these animals are at least our equals, intellectually, and quite possibly more. That we imprison them for our own entertainment is shameful.