Alex Halberstad writing for the New York Times magazine about how modern zoo animals, despite being given better enclosures and more "enrichment" still suffer from mental health disorders.
I wondered, too, why disorders like phobias, depression and OCD, documented at zoos, don’t appear to have analogues among animals living in the wild. Irene Pepperberg, a comparative psychologist at Harvard who is known for her work with African gray parrots, told me that she thought one reason had to do with survival. “An animal in the wild can’t afford to be depressed,” Pepperberg said. “It will simply be killed or starve, since its environment requires constant vigilance. The situation kind of reminds me of my Jewish grandparents, whose lives were a lot harder than mine. They never seemed depressed, because I don’t think it ever occurred to them.”
In other words, we'd all be a lot happier if lions were actually trying to eat us.