Paul M. Gignac, Ph.D., Instructor of Research, Department of Anatomical Sciences, Stony Brook University School of Medicine, and colleagues at Florida State University and in California and Australia, found in a study of all 23 living crocodilian species that crocodiles can kill with the strongest bite force measured for any living animal. The study also revealed that the bite forces of the largest extinct crocodilians exceeded 23,000 pounds, a force two-times greater than the mighty Tyrannosaurus rex.

Their data, reported online in PLoS One, contributes to the understanding of performance in animals from the past and provides unprecedented insight into how evolution has shaped that performance.

In "Insights into the Ecology and Evolutionary Success of Crocodilians Revealed through Bite-Force and Tooth-Pressure Experimentation," the researchers detail their examination of the bite force and tooth pressure of every species of alligator, crocodile, caiman, and gharial. Led by Project Director Gregory Erickson, Ph.D., Professor of Biological Science at Florida State University, the study took more than a decade to complete and required a diverse team of croc handlers and scientists.

"Crocodiles and alligators are the largest, most successful reptile hunters alive today, and our research illustrates one of the key ways they have maintained that crown," says Dr. Gignac.

The team roped 83 adult alligators and crocodiles and placed a force meter between their back teeth and recorded the bite force. They found that gators and crocs have pound-for-pound comparable maximal bite forces, despite different snouts and teeth. Contrary to previous evolutionary thinking, they determined that bite force was correlated with body size but showed surprisingly little correlation with tooth form, diet, jaw shape, or jaw strength.

Dr. Gignac emphasizes that the study results suggest that once crocodilians evolved their remarkable capacity for force-generation, further adaptive modifications involved changes in body size and the dentition to modify forces and pressures for different diets.

The team has been contacted by editors of the "Guinness Book of World Records" inquiring about the data.

Among living crocodilians, the bite-force champion is a 17-foot saltwater croc, with a force measured at 3,700 pounds.

"This kind of bite is like being pinned beneath the entire roster of the New York Knicks," says Dr. Gignac, illustrating the tremendous force displayed by the living creatures. "But with bone-crushing teeth."

The research was funded by the National Geographic Society and the Florida State University College of Arts and Sciences.