There are no known examples of persistently addictive behaviors in the natural world. Of course, we cannot predict exactly what might happen if wild animals had free and easy access to addictive substances in the purified and potent forms administered in laboratories. What has been shown, however, is that conditions in the laboratory powerfully influence which animals will succumb to addiction. Among monkeys, for example, subordinate males who are stressed and relatively isolated are the ones more likely to self-administer cocaine.
