Robert Dudley in the Panamanian rain forest

Research Bio

Robert Dudley is a Distinguished Professor in the Department of Integrative Biology, and a Research Associate at the Smithsonian Tropical Research Institute in Panama. His research is primarily concerned with the evolution, physiology, and biomechanics of flight in insects and hummingbirds. To date, he has published two books and more than 180 research articles in the general fields of biomechanics and comparative physiology. His current research focuses on the origins of flight in birds and insects, and on the amazing flight performance of hummingbirds, a species-rich group which exemplifies up-regulated aerodynamic and physiological capacity.  Laboratory studies of flight biomechanics are complemented by fieldwork to evaluate high-altitude adaptations of volant taxa (e.g., flight performance of bumblebees in the mountains of western Sichuan), comparisons of hummingbirds with the Old World nectarivorous sunbirds, the ecophysiology of long-distance migration in butterflies, and controlled aerial behavior in wingless arthropods of the tropical rainforest canopy. In addition to his work on animal flight, Professor Dudley has pioneered research into the comparative biology of dietary ethanol consumption, with particular reference to those fermenting fruits consumed by primates and human ancestors in tropical rainforests (i.e., the "drunken monkey" hypothesis).

Research Expertise and Interest

metabolism, biomechanics, butterflies, energetics, flight, gliding, hummingbirds, insects, paleophysiology

In the News

Skydiving Salamanders Live in World’s Tallest Trees

Salamanders that live their entire lives in the crowns of the world’s tallest trees, California’s coast redwoods, have evolved a behavior well-adapted to the dangers of falling from high places: the ability to parachute, glide and maneuver in mid-air.

Monkeys Often Eat Fruit Containing Alcohol, Shedding Light on Our Taste for Booze

For 25 years, UC Berkeley biologist Robert Dudley has been intrigued by humans’ love of alcohol. In 2014, he wrote a book proposing that our attraction to booze arose millions of years ago, when our ape and monkey ancestors discovered that the scent of alcohol led them to ripe, fermenting and nutritious fruit. A new study now supports this idea, which Dudley calls the “drunken monkey” hypothesis.

Drunken monkeys: what animals tell us about our thirst for booze

Robert Dudley, an evolutionary physiologist and professor of integrative biology, discusses his new book, “The Drunken Monkey, Why we drink and abuse alcohol” (UC Press 2014). Dudley talks about his motivations for writing the book, the evidence that our attraction to alcohol is an evolutionary adaptation, and what this means for efforts to prevent alcohol abuse.

How hummingbirds shake off the rain

Ever wonder how birds are able to fly in the rain? Robert Dudley and Victor Ortega-Jimenez showed that hummingbirds shake their heads with 34 g’s of force, much like a dog flings off water. But hummingbirds do this in flight in the heaviest downpour without losing control.

Featured in the Media

Please note: The views and opinions expressed in these articles are those of the authors and do not necessarily reflect the official policy or positions of UC Berkeley.
April 5, 2022
Cassandre Coyer
A new study shows that humans' tendency to drink alcohol might come from our primates' ancestors. The study published last month revealed findings that support the "drunken monkey hypothesis." Between June to September 2013, researchers observed the eating tendencies of black-handed spider monkeys for 12 hours each day on Barro Colorado Island in Panama. The monkeys are probably not getting drunk, University of California, Berkeley biologist Robert Dudley, who co-authored the study , said. In a 2014 book, "The Drunken Monkey: Why We Drink and Abuse Alcohol," Dudley explained some fruits eaten by primates have a "naturally high alcohol content of up to 7%." But he did not have data illustrating apes or monkeys sought out and preferred fermented fruits. "It (the study) is a direct test of the drunken monkey hypothesis," Dudley said in a news release. "Part one, there is ethanol in the food they're eating, and they're eating a lot of fruit. Then, part two, they're actually metabolizing alcohol — secondary metabolites, ethyl glucuronide and ethyl sulfate are coming out in the urine. What we don't know is how much of it they're eating and what the effects are behaviorally and physiologically. But it's confirmatory." This story appeared in dozens of media outlets. For more, see our press release at Berkeley News.
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