Being held in captivity is psychologically and physically detrimental to an animal. It can lead to the development of physical and mental illnesses and lead to more violent interactions. Sometimes, zookeepers use prescription drugs to improve the behavior of animals. Animal behavioralists have proven that animals can develop different disorders such as depression, obsessive-compulsive disorder, obesity, and anxiety. Being trapped in an enclosure worsens an animal's mental state and overall quality of life. For example, a killer whale that is responsible for multiple human deaths was shown to be held alone in a small tank, provoking violent behavior. Elephants in captivity are more likely to be stressed and obese. Wild elephants live decades longer than ones kept in zoos. A captive bear has even developed OCD. It repeatedly slammed its head against the metal bars of its enclosure.
Not all zoo animals develop physical or mental illnesses. In fact, living in a zoo may be less stressful than living in the wild. The animal does not have to search or kill for food, water, or shelter since it is already provided by zookeepers. Since the animal has everything it needs, it will not be stressed about surviving.
[P1] Being held in captivity psychologically harms an animal. [P2] Being held in captivity physically harms an animal. [P3] Animals develop mental illnesses from living in zoos.
Rejecting the premises
[Rejecting P2] Not all animals are physically ill in captivity. [Rejecting P3] Not all animals develop a mental illness in captivity.