A decline in ancient megafauna in the Middle East coincided with a shift, visible in the archaeological record, to smaller, lighter toolkits. Smaller fangs or bigger brains? Scientists continue to debate the reasons for this transformation, and the causal relationships.
A drop in the number of large animals between 400 and 200 thousand years ago may have forced ancient humans to abandon their habitats. heavy tools of stone in favor of light setsmore suitable for hunting smaller animals.
This is the conclusion of a new one, published at the beginning of the month in Quaternary Science Reviewswhich gives strength to the idea that the transition to small prey may have driven by intelligence of our ancestors.
For more than a million yearsseveral early human species used similar types of heavy stone tools, such as axes, cleaversscrapers and stone balls.
The remains suggest that these tools were used to kill and dismantle large herbivorous prey, or megaherbivoresincluding now-extinct relatives of elephants, hippos and rhinos.
Then, enter 400 thousand and 200 thousand years agomore tools began to emerge small and sophisticated, on par with heavy tools. Our species, A wise man, appeared in the middle of this period.
Around 200 thousand years ago, heavy tools disappearedcuriously, from the archaeological record in the Levant. At the same time, the number of small, lightweight stone tool sets, including blades and precision scrapersmore sophisticated and diversified.
Now, Vlad Litova researcher at Tel Aviv University in Israel, and his colleagues found a link between this apparent technological change and a sharp decline of large mammals herbivores of the time, possibly decimated by excessive hunting.
Researchers have cataloged archaeological finds from 47 known sites across the Levant throughout the Paleolithic era, which lasted between about 3.3 million years ago and 12,000 years ago. When they matched all the dated stone artifacts with the animal remains found at each site, an intriguing pattern emerged.
The team found that after 200,000 years ago, when heavy technologies disappeared from the record, there was a significant drop in relative abundance, in number of specimens and contribution to biomass of mega-herbivores weighing more than 1000 kilos.
In contrast, the presence and availability of smaller prey increased, along with the number of more sophisticated small tools.
Reinforcing the link between stone tools and prey types, the team also highlights that previous studies have shown that heavy tools persisted until around 50 thousand years ago in other regions where large prey continued to exist, such as in southern China.
Previous hypotheses suggested that this technological change occurred because humans were already more intelligent and innovativepossibly due to as yet unknown evolutionary pressures and advantageous genetic mutations.
But Litov and his team argue that the results support a different idea, one they have proposed before: that dependence on smaller prey boosted the evolution of bigger brains us modern humans.
“As megaherbivores declined, humans became increasingly dependent on smaller prey, which required different hunting strategies, more flexible planning and the use of lighter and more complex tool sets,” says Litov, quoted by .
“These challenges favored cognitive abilities more developed, meaning that cognition evolved as part of this new adaptive system, rather than driving it from the beginning,” he adds.
“I would say that There’s more to this story than just the size of the presa”, he says Ceri Shiptonfrom University College London.
According to the researcher, several studies show that were already underway cognitive changes and more sophisticated forms of planning in the Middle Paleolithic, with still preliminary evidence of mass hunting of ungulates medium sizeincluding horses and bison.
Nicolas Teyssandierdo National Center for Scientific Research, in France, also expresses reservations. “If humans adapted to a new fauna, this reflects adaptation and not pure intelligence”, he states.
“Produce and select heavy technologies to hunt and consume large mega-herbivores It was also a smart way to act”, notes the researcher.
Litov acknowledges that his previous work, as well as that of other researchers, points to highly developed cognitive abilities in the early stages of human evolution, in particular in Homo erectus, which emerged about 2 million years ago.
Still, it maintains that the transition from large prey to small prey had a profound effect on humans. The carcass of an ancient elephant could feed a group of about 35 hunter-gatherers for months.
If these rhigh-calorie foods disappeared, turning to smaller prey would mean a lower energy return per animal, says the researcher.
“From an energy point of view, it was necessary to capture dozens of ungulates smaller ones, like deer, to compensate for the loss of a single elephant”, highlights Litov. “This could have triggered a set of changes cognitive and behavioral challenges, including more intense coordinated hunting of elusive prey, the development of more complex technologies, and enhanced social cooperation and planning.
“These demands may have contributed to the selection for larger brains in later species, including Neanderthals and Homo sapiens,” he adds.
“My personal opinion is that the decline of the large prey items that hominins were accustomed tomay have increased competition between groups,” says Shipton.
“In reality, it will have been probably an iterative processin which the reduction in larger prey drove cognitive changes that, in turn, allowed access to smaller prey”, he concludes.
