New research suggests climate change may have contributed to extinction of Neanderthals. Evidence shows that as the climate got colder, Neanderthals had to put more work into getting their food.
A researcher at the University of Colorado Denver has found that Neanderthals in Europe showed signs of nutritional stress during periods of extreme cold, suggesting climate change may have contributed to their demise around 40,000 years ago.
Jamie Hodgkins, a zooarchaeologist and assistant professor in the Department of Anthropology at CU Denver, analyzed the remains of prey animals and found that Neanderthals worked especially hard to extract every calorie from the meat and bones during colder time periods. Her results were published in the Journal of Human Evolution last week.
Hodgkins examined bones discovered in caves once inhabited by Neanderthals in southwestern France for marks demonstrating how the carcasses of deer and other animals were butchered and used for food. During colder, glacial periods, the bones were more heavily processed. In particular, they showed higher frequencies of percussion marks, indicating a nutritional need to consume all of the marrow, probably signaling reduced food availability.
“Our research uncovers a pattern showing that cold, harsh environments were stressful for Neanderthals,” said Hodgkins. “As the climate got colder, Neanderthals had to put more into extracting nutrients from bones. This is especially apparent in evidence that reveals Neanderthals attempted to break open even low marrow yield bones, like the small bones of the feet.”
These findings further support the hypothesis that changing climate was a factor in Neanderthal extinction.
“Our results illustrate that climate change has real effects,” said Hodgkins. “Studying Neanderthal behavior is an opportunity to understand how a rapidly changing climate affected our closest human relatives in the past. If Neanderthal populations were already on the edge of survival at the end of the Ice Age, the increased competition that occurred when modern humans appeared on the scene may have pushed them over the edge.”
Neandertals disappeared from Europe just after 40,000 years ago. Some hypotheses ascribe this to numerous population crashes associated with glacial cycles in the late Pleistocene. The goal of this paper is to test the hypothesis that glacial periods stressed Neandertal populations. If cold climates stressed Neandertals, their subsistence behaviors may have changed—requiring intensified use of prey through more extensive nutrient extraction from faunal carcasses. To test this, an analysis of Neandertal butchering was conducted on medium sized bovid/cervid remains composed of predominately red deer (Cervus elaphus), reindeer (Rangifer tarandus), and roe deer (Capreolus caprelous) deposited during global warm and cold phases from two French sites: Pech de l’Azé IV (Pech IV, Bordes’ excavation) and Roc de Marsal (RDM). Analysis of surface modification on high survival long bones and proximal and middle phalanges demonstrates that skeletal elements excavated from the cold levels (RDM Level 4, Pech IV Level I2) at each cave have more cut marks and percussion marks than elements from the warm levels (RDM Level 9, Pech IV Level Y-Z) after controlling for fragment size. At both sites, epiphyseal fragments are rare, and although this pattern can result from carnivore consumption, carnivore tooth marks are almost nonexistent (<0.1%). Alternatively, processing epiphyseal ends for bone grease may have been a Neandertal survival strategy, and epiphyses were more intensively percussed in cold levels than in warm levels at both RDM and Pech IV. The exploitation of low marrow yield elements such as phalanges does not show a consistent pattern relating to climate, but may have been a general Neandertal behavioral characteristic, suggesting that these hominids were regularly on the edge of sufficient nutrient availability even during interglacials. Overall, the faunal assemblages from Roc de Marsal and Pech IV provide some support for the hypothesis that Neandertals were processing faunal remains more heavily during glacial periods, suggesting a response to increased nutritional stress during colder time periods.
Jamie Hodgkins, Curtis W. Marean, Alain Turq, Dennis Sandgathe, Shannon J.P. Mcpherson and Harold Dibble; Climate-mediated shifts in Neandertal subsistence behaviors at Pech de l’Azé IV and Roc de Marsal (Dordogne Valley, France); Journal of Human Evolution, doi:10.1016/j.jhevol.2016.03.009.