Humans encircled the globe in 300,000 years. Genetic evolution would have needed 88 million years to get us there — and would have fragmented us into 2,200 separate species along the way.
That's the calculation Charles Perreault, evolutionary anthropologist at Arizona State University, published in Proceedings of the National Academy of Sciences USA. He built a quantitative yardstick for how much “evolutionary work” mammals must do to expand their geographic range, then held humans up against it.
The 88-Million-Year Gap
Perreault compiled range maps for nearly 6,000 mammal species and mapped how geographic spread correlates with three proxies of evolutionary change within a lineage: age, number of descendant species, and body-size diversity. These relationships let him estimate how much genetic adaptation is required to colonize a given area.
By that metric, Homo sapiens did in a few hundred millennia what a typical mammal lineage would need 88 million years to accomplish. We occupy as much terrain as all other mammals combined. (Gray wolves come closest, covering half as much land.)
Cultural Shortcuts Beat Natural Selection
“We can just skip that,” Perreault says of waiting generations for natural selection to produce adaptations. Culture — a continuous stream of better tools, smarter ideas, and more effective practices — accelerates the pace of evolution without rewriting a single gene.
The Kalahari hunter-gatherers might not last long in Greenland, and the Inuit wouldn't fare well in the Kalahari. Each group perfected survival in a vastly different niche, but the collective knowledge pool of humanity covers every terrestrial climate. That's cultural evolution in action: specialized local knowledge shared, accumulated, and transmitted across generations.
What This Means for Understanding Human Exceptionalism
Alex Mesoudi, who studies cultural evolution at the University of Exeter, calls Perreault's paper “a nice attempt to quantify something that we often write but don't actually put any numbers on.” Indeed, the vague claim that culture made us dominant now has a concrete number: 300 times faster than genetics alone.
That number reframes the debate. It's not that humans are biologically superior generalists — we're biologically mediocre generalists with a superlative cultural operating system. Perreault's method gives us a quantitative handle on an old idea, and it suggests our cultural engine is orders of magnitude more powerful than biology alone.
Source: Humans conquered the planet 300 times faster than genetic evolution can explain
Domain: scientificamerican.com
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