In the dense, fruit-laden forests of Africa, a previously overlooked behavior may hold the key to understanding a fundamental aspect of human evolution: our remarkable ability to metabolize alcohol. This behavior, freshly dubbed “scrumping” by researchers from Dartmouth College and the University of St Andrews, refers to the fondness African apes exhibit for consuming ripe, fermented fruit found on the forest floor. By giving this behavior a name, scientists hope to redefine how we perceive the evolutionary relationship between primates and alcohol—a connection that may have shaped the genetic and physiological makeup of modern humans.
At first glance, eating fermented fruit might seem like an unremarkable component of an ape’s diet, but recent studies suggest otherwise. The foundational research dates back to 2015, when geneticists discovered that a single amino acid substitution in the last common ancestor shared by humans and African apes enhanced the efficiency of alcohol-metabolizing enzymes by a staggering 40-fold. This enzyme, alcohol dehydrogenase 4 (ADH4), plays a critical role in breaking down ethanol—the intoxicating compound found in fermented fruit and beverages. While these findings pointed to a genetic adaptation for alcohol metabolism, the ecological and behavioral contexts of this trait remained elusive until now.
The Dartmouth-St Andrews team sought to fill this gap by conducting an extensive literature review of dietary habits across great apes, including chimpanzees, gorillas, and orangutans. Their innovative approach involved not just cataloging what these primates ate but cross-referencing feeding events with the height at which fruits naturally grow in the forest. Crucially, when an ape consumes a fruit at ground level that typically grows in the canopy, it was classified as scrumping—a behavior indicative of deliberate consumption of windfallen, potentially fermented fruit.
Their findings revealed a striking pattern: African great apes engage in scrumping regularly, whereas orangutans, which inhabit Southeast Asian forests, display this behavior scarcely, if at all. This divergence supports biochemical analyses showing that orangutans possess much less efficient enzymes for metabolizing ethanol. The implication is that the consumption of fermented fruits—and the genetic adaptations enabling safe ethanol metabolism—emerged uniquely within the evolutionary lineage leading to African apes and humans.
This evolutionary niche is especially intriguing because it may have conferred significant survival advantages. By embracing fermented, ground-level fruits, long before the advent of deliberate alcoholic beverage production, these apes could avoid competing with smaller primates, such as monkeys, for unripe canopy fruits. Additionally, foraging on the forest floor reduces the hazard of tree climbing, a risky activity that has been implicated in shaping human anatomical features such as shoulder and elbow joints to mitigate falls. As such, scrumping may have influenced not only dietary strategies but also critical aspects of human physiology and risk management.
The daily dietary estimate for chimpanzees—roughly 10 pounds of fruit—suggests they may ingest considerable quantities of ethanol regularly, leading to chronic, low-level exposure. This level of intake, the researchers argue, could exert selective pressures shaping the metabolic pathways that allow humans superior tolerance and processing of alcohol. The metabolic sophistication evident in humans, long thought to be a byproduct of cultural innovation in alcohol production, might instead be deeply rooted in ecological interactions shared with our primate ancestors millions of years ago.
Going forward, the scientists emphasize the need to quantify fermentation levels in both canopy and ground-level fruits to refine estimates of alcohol exposure in these primates. Understanding the biochemistry of these fruits and the microbiota responsible for fermentation could illuminate the evolutionary timeline for alcohol metabolism adaptations. This line of inquiry opens a fascinating window into how dietary ecology translates into genomic and physiological evolution.
Beyond metabolism, scrumping also intersects with social behavior—a domain where apes share interesting parallels with humans. Catherine Hobaiter, a co-corresponding author from the University of St Andrews, highlights that humans’ relationship with alcohol transcends mere consumption; it is fundamentally a social act. From casual pub gatherings to monumental feasts, drinking alcohol often facilitates bonding and social cohesion. Whether fermented fruit consumption similarly fosters social interactions among apes remains an intriguing question for future studies to address.
The introduction of “scrumping” into scientific discourse addresses a long-standing lexical void that has masked the significance of this behavior. Much like how “symbiosis” transformed biological thinking in the 19th century or “meme” revolutionized cultural evolution studies in the 20th century, the researchers anticipate that scrumping will gain traction if it proves useful in framing further research. Terminology in science is not merely semantic but fundamentally shapes the contours of inquiry and conceptual understanding.
This study exemplifies how interdisciplinary collaboration—melding anthropology, evolutionary biology, primatology, and biochemistry—can yield fresh perspectives on longstanding evolutionary puzzles. By reframing behaviors in ecological and genetic contexts, the team not only charts new research pathways but reinvigorates debates about the origins of human uniqueness, especially regarding diet and sociality.
Scrumping reframes fermented fruit consumption as an adaptive behavior rather than an incidental dietary quirk. It invites us to reconsider that the roots of human alcohol consumption predate agriculture, brewing, and modern libations by millions of years, embedded instead in the survival strategies of our primate ancestors. By understanding the complex interplay between ecological habits and genetic evolution, this research underscores the intricate web of factors that shaped the trajectory of human biology.
In the broader scope of human evolution, the capacity to metabolize alcohol may have been a crucial factor enabling early humans to exploit novel ecological niches. The Neolithic Revolution, typified by the transition from foraging to farming, included the domestication of fermentable crops and the manufacture of alcoholic beverages—an innovation that propelled social and cultural transformations. Yet this new work suggests that the biochemical tools necessary for processing alcohol were in place long beforehand, primed by a primate legacy of scrumping.
The implications of this research extend beyond evolutionary history. Understanding how low-level ethanol exposure shaped metabolic and social adaptations offers insights relevant to modern health sciences, including metabolism, nutrition, and the complex interplay between genetics and environment. It also enriches our understanding of the deep origins of human social behaviors linked with alcohol consumption.
As scientific investigation continues, the inclusion of scrumping as a distinct behavioral category promises to sharpen ecological and evolutionary studies of primates. It is a reminder that sometimes, the most profound insights emerge from redefining the concepts and terms with which we engage the natural world.
Subject of Research: Animals
Article Title: Fermented fruits: scrumping, sharing, and the origin of feasting
News Publication Date: 31-Jul-2025
Web References: http://dx.doi.org/10.1093/biosci/biaf102
Image Credits: Catherine Hobaiter / University of St Andrews
Keywords: Evolution, Evolutionary biology, Adaptive evolution, Human evolution, Evolutionary processes, Mammals, Nonhuman primates, Monkeys, Primates, Life sciences, Animals, Vertebrates, Wildlife, Organismal biology, Ecology, Early humans, Human adaptation, Alcoholic beverages, Beverages
