The Evolution of Endurance Running and the Tyranny of Ethnography: A Reply to Pickering and Bunn (2007)

1. What they did

Humans can run long distances as well as or better than many mammals built for running, such as dogs and horses. In 2004, Bramble and Lieberman argued that this endurance running (ER) ability was selected for in the genus Homo, probably by the time Homo erectus appeared, about 1.9 million years ago. One idea is that it helped early humans hunt by persistence hunting (PH), and scavenge.

Pickering and Bunn (2007) criticised this idea on two grounds: that early Homo lacked the tracking ability needed for persistence hunts, and that modern hunter-gatherers rarely run to hunt or scavenge. In this short reply, the authors answer both points, using published evidence from animal behaviour, physiology, archaeology and ethnography (studies of living peoples). They argue that relying only on the recent ethnographic record to explain the past, what Wobst (1978) called the “tyranny of ethnography”, is a flawed approach.

2. What they found

Tracking abilities

• There is no evidence that early Homo could not track. Tracking is complex and takes years of practice (Liebenberg 1990), but many mammals with much smaller brains than any hominid track using smell, sound and sight. Human tracking by smell is also underrated.
• Homo erectus made tools needing up to 30 flake removals from one core, and by 1.7 million years ago made symmetrical handaxes that needed a mental template.
• However they hunted, early humans without good projectile weapons would have needed to track wounded prey. The authors propose that tracking is as old as hunting, and was more, not less, important in the Early Stone Age (ESA). They accept this will be hard to test.

Hunting without weapons

• Early Homo had no serious weapons. Handaxes work poorly as projectiles, and claims that spheroids were bola stones are a myth. Sharpened wooden spears are more likely, but early Homo did not make stone- or bone-tipped spears, and the bow and arrow and the spear thrower were not invented until after modern humans (Homo sapiens) appeared.
• Recent hunters such as the Hadza and the Bushmen use bows, poison and tipped spears, so they are poor models for early Homo.
• Thrown spears are cast from only about 8 m on average, mostly at animals already caught or disabled. Getting within a few metres of a large animal is risky: one kick or horn strike could be fatal.
• Walking an animal down is unlikely to work. The point of a persistence hunt is to keep the animal above the speed where it switches from trotting to galloping, until it overheats, not to tire it. Galloping mammals cannot pant to lose heat, while walking or trotting mammals can, for very long distances.
• Running is only about 30% more costly than walking over the same distance. In their example, a three-hour hunt costs about 700 kcal walking or 910 kcal running. A 13 kg duiker yields about 15,600 kcal; a 200 kg animal such as a kudu or wildebeest yields about 240,000 kcal.
• About 50% of the persistence hunts recorded by Liebenberg (2006) succeeded, giving about 70% more meat per day than bow and arrow hunting. Persistence hunting has been recorded among the Kalahari Bushmen, the Tarahumara of northern Mexico, the Navajo and Paiutes of the American Southwest, and Australian Aborigines. Bushmen have depended less on hunting since the 1960s, so its rarity today says little about the past.

Scavenging

• Hyenas run mostly at dawn, dusk and night because of the heat. Runners able to cover long distances in daytime heat could reach carcasses first, for example after spotting vultures many kilometres away. Hadza who see a scavenging chance “move quickly to the spot, often at a run”.
• Modern foragers often drive lions or hyenas off kills with weapons. Early Homo was neither strong nor armed, so speed may have mattered even more.
• Early humans may also have followed migrating herds, scavenging fresh carcasses and running down the very young or weakened adults.

3. What they concluded

• The modern ethnographic record is limited, biased and sometimes misleading evidence for how ESA hominids hunted and scavenged. Past behaviour should be explained with testable hypotheses from actualistic (present-day experimental and observational) studies.
• Several lines of evidence suggest that endurance running would have helped early humans hunt and scavenge with only ESA technology, and may have let early Homo take up a new niche as a daytime social carnivore.
• They do not claim that persistence hunting was the only way to hunt, that all scavenging depended on running, or that Homo erectus could run as well as modern humans. Only that Homo erectus could run long distances to some extent, and that this would have increased their fitness.

4. How tracking was or was not used

No tracking was done for this paper. Tracking is a central topic: the authors argue that early Homo would have had the tracking skills needed for persistence hunting and for following wounded prey, and that tracking is as old as hunting.