Featured Research

from universities, journals, and other organizations

Early Humans Had 'Jaws Of Steel'

Date:
February 3, 2009
Source:
Arizona State University
Summary:
New research reveals nut-cracking abilities in our 2.5-million-year-old relatives that enabled them to alter their diet to adapt to changes in food sources in their environment. Computer simulation shows early humans had jaws to eat diet of hard seeds and nuts.

Compressive stress in the cranium of Australopithecus africanus, an extinct early human, imposed by biting on the premolar teeth. Bright colors correspond to high stresses, and indicate that a bony pillar running alongside the opening of the nasal cavity acts as a strut that structurally reinforces the face against premolar loads.
Credit: Image courtesy of Arizona State University and the "Hominid Feeding Biomechanics" research team

Your mother always told you not to use your teeth as tools to open something hard, and she was right. Human skulls have small faces and teeth and are not well-equipped to bite down forcefully on hard objects. Not so of our earliest ancestors, say scientists.

New research published in the February 2009 issue of Proceedings of the National Academy of Sciences reveals nut-cracking abilities in our 2.5-million-year-old relatives that enabled them to alter their diet to adapt to changes in food sources in their environment.

Mark Spencer, an Arizona State University assistant professor, and doctoral student Caitlin Schrein in ASU's School of Human Evolution and Social Change, are part of the international team of researchers who devised the study featured in the article "The feeding biomechanics and dietary ecology of Australopithecus africanus." Using state-of-the-art computer modeling and simulation technology – the same kind engineers use to simulate how a car reacts to forces in a front-end collision – evolutionary scientists built a virtual model of the A. africanus skull and were able to see just how the jaw operated and what forces it could produce.

"We started with a CT scan of a skull that is one of the most complete specimens of A. africanus that we have," said Spencer, researcher in ASU's Institute of Human Origins and a lead investigator on the project, which was funded by the National Science Foundation and European Union. This would be a later relative of Lucy – STS5 - who is affectionately known as "Mrs. Ples." The skull, discovered in 1947, has struts on the side of the nose, but no teeth. "We meshed those data with another specimen with teeth to make the virtual model of the bone and tooth structure.

"Then we looked at chimpanzees, who share common features with Australopithecus, and took measurements of how their muscles work and added that to the model. We were able to validate this model by comparing it to a similar model built for a species of monkey called macaques," Spencer explained.

The result – a rainbow colored virtual skull that illustrates forces absorbed by the cranial structure in simulated bite scenarios and how their unusual facial features were ideally suited to support the heavy loads of cracking hard nuts.

"It was like watching 'Mrs. Ples' come to life," Spencer said.

"This reinforces the body of research indicating that facial specializations in species of early humans are adaptations due to a specialized diet," said Spencer. "The enlargement of the premolars, the heavy tooth enamel and the evidence now that they were loading forcefully on the molars suggest the size of the objects were larger than the previously hypothesized small seeds and nuts.

"These fall-back foods – hard nuts and seeds – were important survival strategies during a period of changing climates and food scarcity," he added. "Our research shows that early, pre-stone tool human ancestors solved problems with their jaws that modern humans would have solved with tools."


Story Source:

The above story is based on materials provided by Arizona State University. Note: Materials may be edited for content and length.


Journal Reference:

  1. David S. Strait, Gerhard W. Weber, Simon Neubauer, Janine Chalk, Brian G. Richmond, Peter W. Lucas, Mark A. Spencer, Caitlin Schrein, Paul C. Dechow, Callum F. Ross, Ian R. Grosse, Barth W. Wright, Paul Constantino, Bernard A. Wood, Brian Lawn, William L. Hylander, Qian Wang, Craig Byron, Dennis E. Slice, and Amanda L. Smith. The feeding biomechanics and dietary ecology of Australopithecus africanus. PNAS, 2009; DOI: 10.1073/pnas.0808730106

Cite This Page:

Arizona State University. "Early Humans Had 'Jaws Of Steel'." ScienceDaily. ScienceDaily, 3 February 2009. <www.sciencedaily.com/releases/2009/02/090203093125.htm>.
Arizona State University. (2009, February 3). Early Humans Had 'Jaws Of Steel'. ScienceDaily. Retrieved August 29, 2014 from www.sciencedaily.com/releases/2009/02/090203093125.htm
Arizona State University. "Early Humans Had 'Jaws Of Steel'." ScienceDaily. www.sciencedaily.com/releases/2009/02/090203093125.htm (accessed August 29, 2014).

Share This




More Fossils & Ruins News

Friday, August 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Minds Blown: Scientists Develop Fish That Walk On Land

Minds Blown: Scientists Develop Fish That Walk On Land

Newsy (Aug. 28, 2014) Canadian scientists looking into the very first land animals took a fish out of water and forced it to walk. Video provided by Newsy
Powered by NewsLook.com
40,000-Year-Old Mammoth Skeleton Found On Texas Farm

40,000-Year-Old Mammoth Skeleton Found On Texas Farm

Newsy (Aug. 26, 2014) A mammoth skeleton was discovered in a gravel pit on Wayne McEwen's Texas farm back in May. It's now being donated to a museum. Video provided by Newsy
Powered by NewsLook.com
Pawn Shop Buys Lincoln Signature For $50, Worth $50,000

Pawn Shop Buys Lincoln Signature For $50, Worth $50,000

Newsy (Aug. 25, 2014) The signature is one of a couple Lincoln autographs that have popped up recently. Video provided by Newsy
Powered by NewsLook.com
Neanderthals Probably Died Out Earlier Than We Thought

Neanderthals Probably Died Out Earlier Than We Thought

Newsy (Aug. 21, 2014) A new study is packed with interesting Neanderthal-related findings, including a "definitive answer" to when they went extinct. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins