Zoos primary purpose is entertainment not conservation. choose the best piece of evidence to support the reason. american law requires only that animals in zoos be provided with enough space for them to stand up, lie down, turn around, and take a few steps. animals in zoos may have a mental breakdown and develop "zoochosis," a form of psychosis that can cause them to sway or pace continually, chew on their own limbs until they bleed, or pull out their own fur/feathers. zoos dispense antidepressants and other drugs to curb abnormal and self-destructive behavior. scientists struggle to learn anything about natural behavior from animals that are forced to live in an unnatural setting.