Upright Posture, Endurance Hunting and Human Imagination
It's easy to get jealous watching other primates in the trees. The way chimpanzees hook easily from one branch to the next, scale a bare trunk in seconds or grip and swing from their feet, you might begin to feel that, superior intelligence aside, your human body is comparatively deficient. Apes tend to be stronger than us, with dense musculature that makes them fierce fighters and easy gymnasts.
But guess what? Our advantages over apes are not strictly intellectual. Your average Homo sapiens has a physical capability that apes -- and, as it turns out, most other mammals -- don't have: We're natural long-distance runners.
Many mammals, especially the four-legged kind, can run very fast over short distances. They're built for it, with strong muscles, adaptable circulatory systems, efficient joints and so forth. But what they can't seem to do is keep up with well-conditioned human runners when the distance really sets in.
This 2009 New York Times article compiles some of the research on running and human origins, mentioning a few of the key anatomical differences at play here. For one thing, humans are especially good at keeping our bodies cool, which is extremely important after miles of exertion. When our bodies begin to overheat during vigorous exercise, we cool them with sweating rather than panting. We also have relatively little body hair, which helps the sweat evaporate quickly and generally increases contact between the skin and the air. But that's not all: Our posture, our lower body muscles, the bone structure of our feet -- all of these things are optimized for long-distance running. You might envy a chimpanzee's opposed, thumb-like big toe, since it lets her grip a branch firmly with her foot, but she in turn might envy your straight big toe, since it acts as a perfect lever for the foot in the act of upright running.
Some of the scientists who have observed these features in human anatomy believe that running is not just something we happen to do well -- it was a fundamental factor in our evolution. Early upright hominids, our ancestors, were probably "persistence hunters," meaning that they caught prey by virtue of their endurance rather than their speed. There's no contest between a sprinting gazelle and a sprinting human. The gazelle leaves us in the dust. But after chasing for 15 miles, 20 miles or more, the scales may tip toward the human hunter, since the gazelle more easily becomes overheated, exhausted and unable to go on.
There's little doubt that long-distance running made us the creatures we are today in a physical sense, but I wonder if endurance running and persistence hunting, these things we apparently do very well, could have anything to do with the way our complex minds developed.
What separates a human from an animal like a dog? Well, dogs possess some intelligence. They can learn tricks, respond to conditioning, solve spatial problems and form complex emotional relationships with humans and with each other. But one thing they really seem to lack is imagination. No matter how smart dogs get, they're unable to form abstract concepts, unable to imagine an object or scenario other than what they're looking at. They live in the present moment. It's hard to imagine your average dog continuing to hunt after its prey has dropped out of sight and the dog has lost the scent. For that, it seems like it would take something almost like imagination, like abstract thinking. The hunter would have to know that the prey is still out there, that it is slowly tiring, and that the hunter will eventually catch up to it, despite the fact that it is, at least temporarily, leaving the hunter far behind. If this kind of hunting really does take something like imagination, could this be the reason that humans are now the only animals on Earth with art, science, music and literature?