Next, they are frequently distracted by visitors. Zoo visitors often have the habit of feeding them human food, which may contain harmful chemicals. Close contact with human beings can cause animals to become domesticated to some degree. In addition, animals are sometimes deprived of basic needs such as food and a clean environment when they are kept in zoos. Large animals consume a lot of food. This can put a lot of financial stress on the zoo. Consequently, the zoo might then contemplate choosing cheaper and thus less healthy options. Some zoos place their animals into small and filthy enclosures, affecting both mental and physical health of their animals.