Falling Out of the Family Tree

A mutation in an ethanol-metabolizing enzyme arose around the time that arboreal primates shifted to a more terrestrial lifestyle, perhaps as an adaptation to eating fermented fruit.

Written byJef Akst
| 4 min read

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THEEZ LOOK LELISHUSS, HIC!: A chimpanzee feeding on the ripe fruits of Parkia bicolorHENRY GBEREGBE

Why are humans so attracted to alcohol, and why do so many struggle with its abuse? These are questions that science still can’t answer. The “drunken monkey” hypothesis proposed by University of California, Berkeley, biologist Robert Dudley posits that, unlike our attraction to other addictive drugs, our use and sometimes dependence on alcohol stems from the millions of years our ancient primate ancestors spent consuming ripe, fermented fruits. Perhaps these predecessors evolved some kind of neurological mechanism that drove them to seek out and consume sugar-rich, ethanol-containing foods, which were likely in short supply millions of years ago. But now that there’s a liquor store on every other corner, that drive to seek out alcohol has turned against us. (See “Drunks and Monkeys,” The Scientist, ...

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  • Jef (an unusual nickname for Jennifer) got her master’s degree from Indiana University in April 2009 studying the mating behavior of seahorses. After four years of diving off the Gulf Coast of Tampa and performing behavioral experiments at the Tennessee Aquarium in Chattanooga, she left research to pursue a career in science writing. As The Scientist's managing editor, Jef edited features and oversaw the production of the TS Digest and quarterly print magazine. In 2022, her feature on uterus transplantation earned first place in the trade category of the Awards for Excellence in Health Care Journalism. She is a member of the National Association of Science Writers.

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