Ancient Humans Were Not Good at Climbing

Anthropologists and archaeologists have been scouting early human dig sites around the world for clues as to when the change from the primate-like state to a biped humanoid happened. They know that, in the grand scheme of things, ancient humans gave up their ability to use all of their four limbs to climb trees, in favor of an upright posture, which would allow them to move more efficiently across the vast savannas, where we first developed. Now, a new study may shed some light as to when that change occurred, experts hope.

LiveScience reports that Worcester State College in Massachusetts (WSC) Anthropologist Jeremy DeSilva conducted a series of compared tests on the matter, analyzing how our closest animal relatives, the chimpanzees, moved. He then cross-referenced the results with several humanoid fossils, dating back as much as 1.5 to 4 million years ago. He uncovered the fact that hominids living more than 4 million years back had already lost their ability to efficiently climb trees, a discovery that reduces the estimated time anthropologists estimated for this transition.

“Frankly, I thought I was going to find that early humans would be quite capable, but their ankle morphology was decidedly maladaptive for the kind of climbing I was seeing in chimps. It kind of reinvented in my mind what they were doing and how they could have survived in an African savanna without the ability to go up in the trees,” DeSilva said. Dorsiflexion represents the ability that feet have to twist their ankles. The more developed this trait, the more the ankle can rotate, until the toes eventually point upwards. After cross-referencing data collected from chimpanzees, early humans and modern humans, he concluded that our 4-million-year-old ancestors were very similar to us as far as ankles were concerned.

“I think by 3 to 4 million years ago that tradeoff was occurring. Our ancestors were becoming very capable upright walkers, and it came at the expense to our ability to climb trees,” the expert added. He also shared that, by that time, our bodies had become adapted to walking upright, in that the weight of the foot and ankle decreased, so as to allow for a more energy-efficient locomotion. Over the following millennia, humans managed to develop a special type of walk, which is to this day the most effective mode of locomotion on the planet, in terms of energy spent and re-captured.