Humans are born to run, and scientists now think they know how this trait evolved

Humans stand out among mammals for our ability to run long distances without falling apart. That ability links back to early human ancestors and how they evolved into endurance runners while learning to hunt animals for food.

A new analysis revisits a classic idea about how our species hunts.

It asks two simple questions: (1) Does it pay, in time and energy, to run animals until they overheat? (2) Did people use that tactic often enough for natural selection to favor bodies built for steady running?

The answers connect physiology, behavior, and plain arithmetic.

How humans learned to run

Skeptics have long raised two objections about this evolutionary theory. Running burns more energy per minute than walking, so why would an early human hunter choose to run instead of walk, and how could this pattern shape evolution?

The study tests those points with equations that track returns over time and with a broad survey of historical accounts.

This study treats hunting as a “rate-of-return” problem. It looks at calories gained from a carcass, subtracts calories burned by the hunter, and divides by the hours spent hunting.

The result is an hourly payoff. If a tactic raises that hourly rate, then it makes sense.

Time, speed, and calories

Speed raises the “calorie cost” each minute, but it also shortens the clock. The model shows that when humans move faster by running, it can increase the hourly payoff because the hunt ends sooner.

When you finish quickly, you stop the “hunting meter.” Even with a higher burn rate per minute, the total time shrinks enough to lift the return per hour.

That shift in perspective – cost per minute versus return per hour – sits at the heart of the study’s first answer.

The model also compares different patterns of movement. It considers jogging, running, or alternating between the two while tracking total distance.

A rhythm that mixes running with brisk walking scores well because it balances pressure on the prey with heat control for the hunter. The method trims the clock without pushing the human past a safe limit.

Understanding heat physiology

Thermal biology makes the strategy workable. Many large-hoofed animals hunted by humans shed heat poorly when they are forced to run for sustained periods. To prevent overheating, they rely heavily on panting.

Panting works best when they can open their mouths and when the surrounding air carries moisture away. Under hard running, especially in warm, still conditions, panting loses efficiency.

Humans cool differently. Bare, sweaty skin and sweat glands spread across most of our bodies that allow us to continually shed heat as we move.

Long legs help with efficient strides, and tendons act like springs that save and release energy with each step. In addition, slow-twitch, fatigue-resistant muscle fibers support this steady effort.

Together, those features allow a human to maintain a sustainable running pace while a pursued animal faces a heat trade-off it cannot ignore.

Documenting centuries of human hunts

The evidence does not stop with equations. The authors assemble firsthand reports from several centuries of diaries, ethnographies, and travel notes. Accounts appear across all continents and environments.

People describe open country chases in heat, winter hunts on crusted snow, and runs along forest edges where visibility allows tracking from a distance. Some reports describe single human runners while others describe relays in which partners trade off.

Across many of those narratives, a shared rhythm appears. Hunters flush the animal, press at a steady, sustainable pace, and close the gap each time the animal slows to cool.

The pattern repeats until the animal can no longer escape. The method does not rely on a sprint; it relies on firm pacing and a prey animal’s rising temperature.

The study compares endurance pursuit to ambushes, group drives, and trapping. It does not claim that running always wins. It shows that conditions decide what pays best per hour.

Open terrain under midday heat tends to favor the runner’s cooling system and clear sightlines. Snow or soft sand can slow heavy hooves more than human feet. Those settings raise the return rate for controlled chases.

How humans’ running ability evolved

Natural selection favors traits that improve success often enough to matter for survival and reproduction. If endurance pursuits worked under common conditions – warm, open landscapes; footing that penalizes heavy animals; clear lines of sight – then bodies that handle steady work would pay off.

Features linked to endurance make sense in that light: long lower limbs that reduce the cost of transport; a robust Achilles tendon that stores and releases energy; a nuchal ligament that stabilizes the head during running; widespread eccrine sweating that cools the skin without stopping motion.

The picture remains balanced. The study does not suggest that our ancestors relied on one tactic. It places endurance alongside other strategies and shows when it can match or exceed them in net returns per hour.

The argument stays modest but clear: repeated payoffs in the right conditions can nudge anatomy in a consistent direction over many generations.

Pace and recovery

The most effective pattern is not an all-out sprint. It is a smart tempo. Short stretches of running push the prey toward its heat limit. Brisk walking intervals manage the hunter’s own heat and energy.

That alternation maintains pressure without collapse. It keeps the chase within the human comfort zone while the prey faces a rising internal cost it cannot ignore.

This pacing approach also reduces wasted motion. Continuous, sustainable tracking tightens the loop each time the animal slows. The gap closes in steps, not in a single burst. Each pause by the prey becomes a chance to gain ground.

The model’s bottom line stays consistent. When a hunter finishes a chase quickly, the hourly energy return climbs, even though running costs more per minute. Time, not just distance, governs the payoff.

Running, hunting, and human evolution

Understanding how endurance pursuits work offers a window into why our bodies look and function the way they do. Linking anatomy, behavior, and environment to ancient hunting strategy, it helps scientists make sense of how humans evolved the ability to run long distances.

It also helps explain why humans in many places still choose long, controlled running for hunts under the right conditions. The tactic makes sense when heat and footing help, when weapons at distance are limited, and when safety matters.

Taken together, the analysis and the records point to a straightforward conclusion. Humans are unusually good at steady running because controlled chases paid off, more often than not.

The full study was published in the journal Nature.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates.

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–