It is well-known that Homo sapiens voluntarily learns to self-administer psychoactive drugs without additional reinforcement. The primary societal use of these self-administrations is social ( et al 1969), while the motivation to repeatedly self-administer is considered a major factor in human drug abuse (cf. 1971). Among the many drugs used in this way by man are the hallucinogens. Indeed, it is a traditional, albeit tacit, assumption of psychopharmacological thinking that Homo sapiens is the only species that will self-administer hallucinogens without additional rewards.
…Conclusion: The ethologic search has found that Homo sapiens is not alone in the self-administration of hallucinogens. Either by accident or design, numerous infrahuman species also self-administer these drugs. Table 2 shows some ethologic examples of the self-administration of various types of drugs as described in this paper. The drug types and their naturally occurring substances are listed together with the animals which self-administer them, pattern of self-administration as discussed in this paper, animals which self-administer the same or similar substances in the laboratory, and the human use of these substances. Of the 14 drugs listed in Table 2, four are hallucinogens and four others are known to have hallucinogenic effects in man. Many of the examples cited here need further controlled psychopharmacological study in order to identify the biological, environmental, and pharmacological variables which reinforce and maintain self-administration. Nonetheless, it is clear that the consequences of such administrations dramatically affect the social behavior of these animals. Whether “sick”, “ill”, “intoxicated”, “poisoned”, “hypersensitive”, “genetically guided”, “narcotized”, or “addicted”, hallucinogen-treated animals tend to isolate themselves from social groups.