The Evolutionary Roots of Alcohol Feasting

Since the previous post was about the role that alcoholic beverages played in domestication, and hence the formation of large-scale societies, I thought I’d share this post that I ran across last week. It goes back to the evolutionary origins of our craving for alcohol.

If it’s correct, it would mean that the seeds for later large-scale social groups were sewn very early in human evolution, even back before we diverged form chimps. Millions of years ago, ancient tree-dwelling primates sought out fermented fruits in the canopy. Millions of years later, this craving would lead to the formation of the first civilizations.

According to the [“drunken monkey” hypothesis, formulated by biologist Robert Dudley in 2000], our pre-human ancestors regularly ingested small amounts of alcohol because the substance is produced when ripe fruit or nectar is decomposed by wild yeast. Through natural fermentation, yeast feeds on plant sugars and produces waste products of CO2 and ethanol — the chemical name for alcohol.

Although this spoils fruit, it presents an opportunity for animals that can digest alcohol. Creatures able to eat fermenting sugars would have an additional source of nutrients. Not only would they consume semi-rotten fruits, passed over by other animals, but alcohol itself has nutritional value: There are nearly twice as many calories in ethanol compared to carbohydrates of the same weight. (While this causes unwanted beer bellies today, extra calories are beneficial in the wild.)

Also, fermentation produces strong odors. An animal attracted to the yeasty scent would be able to follow its nose to edible fruit, and potentially find that food source before creatures without the taste for alcohol. And lastly, as many of us have experienced, alcohol stimulates appetite. Individuals munching on fermented fruit may eat more, obtaining bonus calories and nutrients.

In these ways, developing a taste for alcohol — the low levels found in nature — could have given our ancestors an advantage. In a forest full of animals competing for energy-rich foods, “drunk monkeys” would have access to an untapped resource.

It wasn’t until millions of years later, after Homo sapiens created beverages with unnaturally high ethanol concentrations (i.e. beer, wine, liquor), that alcohol consumption became a social and public health issue. According to Dudley, alcohol abuse and addiction are an “evolutionary hangover” of a deep-routed taste for fermented sugars, adaptive long ago.

‘Drunken Monkey’ Hypothesis: Was Booze an Advantage For Our Ancestors? (Discovery)

Food sharing—the basis for feasting—has been observed in bonobos (but not in chimps):

In the wild, sharing of food by chimps typically happens after a rare hunt, and the “sharing” of meat often involves the passive tolerance of theft or simply giving in to relentless begging and harassment by others.

In contrast, the bonobos voluntarily handed over nuts that were solidly in their possession.

“What we are seeing in bonobos is very unusual,” says Krupenye. “We do see food sharing in other species, but in the vast majority of cases it is that one individual tolerates another taking something from them.”

The finding adds to a growing body of evidence that bonobos are uniquely pro-social when it comes to food…

What’s Mine Is Yours, Sort Of: Bonobos And The Tricky Evolutionary Roots Of Sharing (NPR). And, related, scientists have discovered the oldest known evidence of humans cooking carbohydrates in Africa:

More than 100,000 years ago, humans lived in the caves that dot South Africa’s coastline. With the sea on their doorstep and the Cape’s rich diversity of plant life at their backs, these anatomically modern Homo sapiens flourished. Over several millennia, they collected shells that they used as beads, created toolkits to manufacture red pigment, and sculpted tools from bones.

Now some of these caves, along the country’s southern coast, have shed light on humanity’s earliest-known culinary experiments with carbohydrates, a staple in many modern diets. Small pieces of charred tubers found at the Klasies River site in South Africa date back 120,000 years, making them the earliest-known evidence of H. sapiens cooking carbs, according to recent research published in the Journal of Human Evolution.

The study joins a suite of new findings that illuminate the evolution of our ancestors’ diet. For example, in recent years, scientists have determined that hominins have been eating meat for at least 2.6 million years —with some researchers contending that hominins were butchering bones for marrow as much as 3.4 million years ago. And hominins were roasting nuts, tubers, and seeds about 780,000 years ago. Humans specifically, as another South African find revealed, ate shellfish some 164,000 years ago. And last year, ancient crumbs revealed that H. sapiens has been eating bread for 14,400 years.

Ancient Campfire Remains Hold Oldest-Known Remains of Humans Cooking Starches (Discover)

One thought on “The Evolutionary Roots of Alcohol Feasting

  1. A little off topic for this specific post, but not for this blog as a whole:

    It was reported this week that the City of Chennai, India, home to approximately 4 million people, is almost out of fresh water. It was also reported that the Himalayan glaciers are now melting faster than replacement rate of winter snow. It is now projected that by 2030 (10.5 years from now) 40% of the Indian population (now at 1.38 billion) will be without access to fresh water. This means potentially 600 million refugees on the scene looking for someplace else to live. Surely no government or human social system can stand under such immense stress. Would be curious about your thoughts in future posts.

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