May 11, 2013
Researchers Study Earliest Evidence Of Human Hunting And Scavenging
April Flowers for redOrbit.com — Your Universe Online
New light has been shed on the diet and food acquisition strategies of some of the earliest human ancestors in Africa, according to a new study led by Baylor University.
Early tool making humans, known as Oldowan hominin, started to exhibit a number of physiological and ecological adaptations beginning around two million years ago. These adaptations, including an increase in brain and body size, heavier investment in their offspring and significant home-range expansion, required greater daily energy expenditures. How these early humans acquired the extra energy to sustain these major shifts has been the subject of much debate among researchers.
Joseph Ferraro, PhD, assistant professor of anthropology at Baylor, led the new study that offers insight into the debate with a wealth of archaeological evidence from the two million-year-old site of Kanjera South (KJS), Kenya.
"Considered in total, this study provides important early archaeological evidence for meat eating, hunting and scavenging behaviors - cornerstone adaptations that likely facilitated brain expansion in human evolution, movement of hominins out of Africa and into Eurasia, as well as important shifts in our social behavior, anatomy and physiology," Ferraro said.
KJS is located on the shores of Lake Victoria. The settlement contains “three large, well-preserved, stratified” layers of animal remains, on which the research team worked for more than a decade to recover thousands of animal bones and rudimentary stone tools.
Hominins at KJS met their new energy requirements through an increased reliance on meat eating. The archaeological record at KJS reveals they obtained an abundance of animal remains through a combination of hunting and scavenging behaviors, according to the study. This would make KJS the earliest known archaeological evidence of such behaviors.
"Our study helps inform the 'hunting vs. scavenging' debate in Paleolithic archaeology. The record at KJS shows that it isn't a case of either/or for Oldowan hominins two million years ago. Rather hominins at KJS were clearly doing both," Ferraro said.
The fossil evidence for hominin hunting is particularly compelling, with the record showing that Oldowan hominins obtained and butchered a large quantity of small antelope carcasses. The antelope are well represented at the site, with most or all of their bones from the tops of their heads to the tips of their hooves. This suggests to the scientists they were transported to the site as a whole carcass.
The modern Serengeti is a close environment to KJS two million years ago. Studies of the Serengeti have revealed predators completely devour antelopes of this size within minutes of their deaths, meaning the hominins could have only acquired these animal remains on the savanna through active hunting.
A large number of isolated heads of wildebeest-sized antelopes were also recovered at KJS. Unlike the smaller antelope carcasses, the heads of these larger species are able to be consumed several days after death. This means they could be scavenged, as even the largest predators of the African savanna -- such as lions and hyenas -- were unable to break them open to access their nutrient-rich brains.
"Tool-wielding hominins at KJS, on the other hand, could access this tissue and likely did so by scavenging these heads after the initial non-human hunters had consumed the rest of the carcass," Ferraro said. "KJS hominins not only scavenged these head remains, they also transported them some distance to the archaeological site before breaking them open and consuming the brains. This is important because it provides the earliest archaeological evidence of this type of resource transport behavior in the human lineage."
The results of this study were published in a recent issue of PLOS ONE.