We’ve been hunting animals into extinction for 1.5 million years

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Humans have had a influence on animal extinctions far longer than generally thought and our ancestors had been  hunting species of megafauna into extinction as far again in time as 1.5 million years in the past.

This is in keeping with a crew of scientists at Tel Aviv University in Israel who examined fossil data and argue in a research that prehistoric human hunters tended to want to focus on the biggest prey animals accessible as a result of these animals supplied essentially the most meat after being killed.

After a complete evaluation of knowledge on animal bones collected from dozens of prehistoric websites in and round Israel, the researchers discovered a continuing decline within the dimension of recreation animals hunted by early people as their principal meals supply starting from big elephants 1.5 million years in the past all the way in which to gazelles round 10,000 years in the past.

There is extra: it was solely after animals bigger than deer had been hunted into extinction by the latter date that folks within the so-called Fertile Crescent within the Middle East started to show to farming and domesticating animals, doubtless so as to try to make up for the shortfall in accessible large recreation.

Scientists have lengthy identified that giant animals akin to mammoths disappeared over time from the fossil report, however a basic hypthesis attributed this to adjustments within the local weather.

Members of the Israeli crew posit a brand new cause for these extinctions whereas on the identical time they’ve additionally sought to reply one other query: what drove cultural adjustments in prehistoric human populations as they devised ever extra refined hunting instruments till they finally turned from hunting and gathering to settled farming and animal husbandry.

“In light of previous studies, our team proposed an original hypothesis that links the two questions: We think that large animals went extinct due to overhunting by humans, and that the change in diet and the need to hunt progressively smaller animals may have propelled the changes in humankind,” says Ran Barkai, a professor of prehistoric archaeology at Tel Aviv University.

The researchers centered on the Southern Levant (which encompasses Israel, the Palestinian territories, Jordan, Lebanon and elements of Syria) as a result of the area is an “archaeological laboratory” on account of the density and continuity of prehistoric findings spanning an extended time frame over a comparatively small space.

As a outcome it’s “a unique database unavailable anywhere else in the world,” notes Jacob Dembitzer, a scholar at Tel Aviv University. “Excavations, which began 150 years ago, have produced evidence for the presence of humans, beginning with Homo erectus who arrived 1.5 million years ago, through the Neandertals who lived here from an unknown time until they disappeared about 45,000 years ago, to modern humans (namely, ourselves) who came from Africa in several waves, starting around 180,000 years ago,” Dembitzer says.

Excavations carried out at 58 prehistoric websites since 1932 have supplied a novel sequence of findings from several types of human settlements within the area over 1.5 million years. At some websites numerous human teams lived separated by tens of hundreds of years, their onetime presence now obvious from completely different layers of fossils. In all, hundreds of bones belonging to 83 animal species have been unearthed and recognized.

“Our study tracked changes at a much higher resolution over a considerably longer period of time compared to previous research. The results were illuminating: we found a continual, and very significant, decline in the size of animals hunted by humans over 1.5 million years,” explains Shai Meiri, a professor on the college’s School of Zoology.

“For example, a third of the bones left behind by Homo erectus at sites dated to about a million years ago, belonged to elephants that weighed up to 13 tons (more than twice the weight of the modern African elephant) and provided humans with 90% of their food. The mean weight of all animals hunted by humans at that time was 3 tons, and elephant bones were found at nearly all sites up to 500,000 years ago,” Meiri elucidates.

“Starting about 400,000 years ago, the humans who lived in our region (early ancestors of the Neandertals and Homo sapiens) appear to have hunted mainly deer, along with some larger animals weighing almost a ton, such as wild cattle and horses. Finally, in sites inhabited by modern humans, from about 50,000 to 10,000 years ago, approximately 70% of the bones belong to gazelles — an animal that weighs no more than 20-30kg. Other remains found at these later sites came mostly from fallow deer (about 20%), as well as smaller animals such as hares and turtles,” the scientist provides.

The findings posed a puzzle: What brought on the disappearance of the bigger animals from the realm and human diets over time? Was it local weather change, as a extensively held principle has it, that drove them into extinction? Or was it one thing else?

To see if local weather change was certainly responsible, the scientists collected climatic and environmental knowledge for the whole interval below research overlaying greater than a dozen cycles of glacial and interglacial durations.

“This data included temperatures based on levels of the oxygen 18 isotope, and rainfall and vegetation evidenced by values of carbon 13 from the local Soreq Cave. A range of statistical analyses correlating between animal size and climate, precipitation, and environment, revealed that climate, and climate change, had little, if any, impact on animal extinction,” Dembitzer says.

The perception prompted the Israeli scientists to suggest what Miki Ben-Dor, an professional on the Jacob M. Alkow Department of Archaeology and Ancient Near Eastern Cultures, calls “a fascinating hypothesis on the development of humankind.”

Namely this: “Humans always preferred to hunt the largest animals available in their environment until these became very rare or extinct, forcing the prehistoric hunters to seek the next in size,” Ben-Dor says. “As a result, to obtain the same amount of food, every human species appearing in the Southern Levant was compelled to hunt smaller animals than its predecessor, and consequently had to develop more advanced and effective technologies. Thus, for example, while spears were sufficient for Homo erectus to kill elephants at close range, modern humans developed the bow and arrow to kill fast-running gazelles from a distance.”

Nor is that this speculation restricted to the Levant alone. Rather, the identical tendencies seem to have performed out throughout a lot of the planet, the scientists say.

“We believe that our model is relevant to human cultures everywhere. Moreover, for the first time, we argue that the driving force behind the constant improvement in human technology is the continual decline in the size of game. Ultimately, it may well be that 10,000 years ago in the Southern Levant, animals became too small or too rare to provide humans with sufficient food, and this could be related to the advent of agriculture,” Prof. Barkai observes.

“In addition, we confirmed the hypothesis that the extinction of large animals was caused by humans — who time and time again destroyed their own livelihood through overhunting. We may therefore conclude that humans have always ravaged their environment but were usually clever enough to find solutions for the problems they had created — from the bow and arrow to the agricultural revolution. The environment, however, always paid a devastating price,” the scientist provides.