Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Why you should never arm wrestle a saber-toothed tiger

05.07.2010
X-ray analysis reveals that sabertooth forelimbs were exceptionally strong compared to their feline cousins

Saber-toothed cats may be best known for their supersized canines, but they also had exceptionally strong forelimbs for pinning prey before delivering the fatal bite, says a new study in the journal PLoS ONE.

Commonly called the "saber-toothed tiger," the extinct cat Smilodon fatalis roamed North and South America until 10,000 years ago, preying on large mammals such as bison, camels, mastodons and mammoths. Telltale clues from bones and teeth suggest they relied on their forelimbs as well as their fangs to catch and kill their prey.

The size and shape of sabertooth canines made them more vulnerable to fracture than cats living today, said author Julie Meachen-Samuels, a paleontologist at the National Evolutionary Synthesis Center in Durham, NC.

"Cats living today have canines that are round in cross-section, so they can withstand forces in all directions. If the prey is struggling it doesn't matter which way it's pulling — their teeth are unlikely to break," she explained.

In contrast, the elongated canines of saber-toothed cats were oval in cross-section, which made them more vulnerable to breaking than their conical-toothed cousins. "Many scientists infer that saber-toothed cats killed prey differently from other cats because their teeth were thinner side-to-side," said Meachen-Samuels.

Despite their vulnerable canines, prominent muscle attachment scars on sabertooth limb bones suggest the cat was powerfully built. Saber-toothed cats may have used their muscular arms to immobilize prey and protect their teeth from fracture, she explained.

To estimate how strong sabertooth forelimbs were relative to other cats, the researchers used x-rays to measure the cross-sectional dimensions of the upper arm and leg bones of fossils recovered from the La Brea Tar Pits in Los Angeles. They also measured the limb bones of 28 cat species living today — ranging in size from the 6-pound margay to the 600-pound tiger — as well as the extinct American lion, the largest conical-toothed cat that ever lived.

The researchers used their cross-sectional measurements to estimate bone strength and rigidity for each species. When they plotted rigidity against length for the 30 species in their study, species with longer limbs generally had stronger bones. But the data for the saber-toothed cat fell well outside the normal range —while their leg bones scaled to size, their arm bones were exceptionally thick for their length.

"When I looked at the arm bones, Smilodon fatalis was way out in left field," said Meachen-Samuels.

Sabertooth arm bones were not only larger in diameter than other cats, they also had thicker cortical bone, the dense outer layer that makes bones strong and stiff. Thicker cortical bone is consistent with the idea that sabertooth forelimbs were under greater stress than would be expected for cats their size, Meachen-Samuels explained. Just like weight-bearing exercise remodels our bones and improves bone density over time, the repeated strain of grappling with prey may have resulted in thicker and stronger arm bones in saber-toothed cats.

"As muscles pull on bones, bones respond by getting stronger," said Meachen-Samuels. "Because saber-toothed cats had thicker arm bones we think they must have used their forelimbs more than other cats did."

"The findings give us new information about how strong their forelimbs were and how they were built," she added. "This is the first study to look inside sabertooth arm bones to see exactly how much stress and strain they could handle."

The findings will be published online in the June 30 issue of PLoS ONE.

Blaire Van Valkenburgh of the University of California, Los Angeles was also an author on this study.

CITATION: Meachen-Samuels, J. and B. VanValkenburgh (2010). "Radiographs reveal exceptional forelimb strength in the saber-toothed cat, Smilodon fatalis." PLoS ONE.

The National Evolutionary Synthesis Center (NESCent) is a nonprofit science center dedicated to cross-disciplinary research in evolution. Funded by the National Science Foundation, NESCent is jointly operated by Duke University, The University of North Carolina at Chapel Hill, and North Carolina State University. For more information about research and training opportunities at NESCent, visit www.nescent.org.

Robin Ann Smith | EurekAlert!
Further information:
http://www.nescent.org

More articles from Life Sciences:

nachricht The world's tiniest first responders
21.06.2018 | University of Southern California

nachricht A new toxin in Cholera bacteria discovered by scientists in Umeå
21.06.2018 | Schwedischer Forschungsrat - The Swedish Research Council

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Better model of water under extreme conditions could aid understanding of Earth's mantle

21.06.2018 | Earth Sciences

What are the effects of coral reef marine protected areas?

21.06.2018 | Life Sciences

The Janus head of the South Asian monsoon

21.06.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>