Homo extinctor?

A recent fine-grained archaeological study in the Southern Levant (Eastern Mediterranean region) by the University of Tel-Aviv has brought to light some startling, even disturbing facts about our human ancestors. It covered 58 prehistoric sites and sifted through 133 sedimentary layers in which thousands of bones were found that belonged to 83 animal species.

When the researchers calculated the body weight of the animals found in the layers and correlated the data with the presence of human-like ancestors in the region, they noted from the remains a significant decline in the animal size that were hunted over a period of 1.5 million years.

Elephants of the local mega-fauna were top hunting targets. They weighed 13 tons (or more than two African elephants today). Since elephants bones were found at all sites, archaeologists estimated that this animal provided 90% of the food for the local Homo erectus population. The mean weight of all animals hunted up to 500,000 years ago was 3 tons!

From about 400,000 years ago, early ancestors of the Neanderthals and of Homo Sapiens lived in that region and hunted primarily mega-deer along with other mega-fauna that on average weighed almost 1 ton.

When—from about 50,000 years to 10,000 years ago—modern humans inhabited the region, approximately 70% of the bones found belonged to gazelles weighing a fraction of earlier prey, only about 20-30 kg and from much smaller animals such as hares and turtles.

Given these astonishing results, the researchers were faced with two new questions. What factors other than climate change could potentially account for the disappearance of the mega-fauna in that region? And next, whether the obvious decline in animal body weight in hunted animals had anything to do with it?

When the researchers tested various hypothesis, they discovered that the driver behind mega-fauna extinction was not climate change (as commonly assumed) but human evolution. The data revealed that our prehistoric ancestors hunted the largest animals first and, when these declined, they moved to the next available size, adapting their technology as they went. For instance, when fire-hardened sticks and spears were no longer suitable, they invented bow and arrow to bring down faster-running prey from a distance. At the same time, it is not beyond plausibility that the extinction pressure on huntable animals led to the search for an alternative food source and thus to the evolution of agriculture.

Besides this illuminating research, the researchers discovered something else about us humans that has a remarkably contemporary ring to it: from earliest beginnings, we have ravaged our environment! Yet, in our journey through history, creativity and novelty seem to have come to our rescue “just in time” to save us from extinction, albeit always at a devastatingly high price paid by our environment.



“Early humans hunted the largest animals to extinction over 1.5 million years” (2021, December 21) retrieved from <https://phys.org/news/2021_12-early-humans-largest-animals-extinction.html>




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