The drunken monkey hypothesis proposes that human attraction to ethanol may have a genetic basis due to the high dependence of the primate ancestor of Homo sapiens on fruit as a food source. Ethanol naturally occurs in ripe and overripe fruit and consequently early primates developed a genetically based attraction to the substance. This hypothesis was originally proposed by Dr. Robert Dudley of UC, Berkeley and was the subject of a symposium for the ‘Society for Integrative and Comparative Biology.’
Dudley believes that while most addictive substances are relatively new to humans, ethanol attraction may have a long evolutionarily based history. He believes that fruit ethanol may have been a significant source of energy and that the smell of the ripening fruit would help primates locate it. Ethanol is a light molecule and diffuses rapidly in a natural environment. Primates are known to have a higher olfactory sensitivity to alcohol than other mammals. The once-beneficial attraction to ethanol may underlie human tendencies for alcohol use and alcohol abuse.
The Daily Omnivore 