Research: Alligator Is Animal Kingdom’s Champion Chomper

September 2, 2003

GAINESVILLE, Fla. — The lion has its roar, the cheetah its speed.

But the beast with the most powerful bite? The alligator.

So say three researchers who recently completed a study measuring the force alligators exert when they clamp down their toothy jaws.

American alligators, known scientifically as Alligator mississippiensis, bite harder than any other member of the animal kingdom yet studied, including lions, hyenas, some species of sharks and wolves, not to mention people, said Kent Vliet, a University of Florida zoologist.

In fact, their chomp may even be mightier than some species among history’s most-celebrated masticators, the dinosaurs, he said.

“Alligators do these excruciatingly powerful bites,” he said. “They really just lay into it. You can see their neck muscles flex.”

Vliet is an author of a paper about alligators’ biting prowess that appeared last month in the Journal of Zoology of London. The two others are Gregory Erickson, a professor of anatomy and vertebrate paleobiology at Florida State University in Tallahassee, and Kristopher Lappin, a biologist at Northern Arizona University in Flagstaff.

To test the gators’ bites, the scientists built “bite bars” – metal bars resembling large tuning forks. The bars, which were covered in leather to prevent damage to the alligators’ teeth, contained strain gauges that measure force. The researchers presented the bars, which were of varying length and thickness for different sized alligators, to more than 40 captive gators ranging from about 1 foot to over 12 feet at an alligator farm.

The gators did the rest.

“The hardest part of the work was getting the bite bar back from them, because they’d often hold onto it for 20 minutes, and it is delicate equipment,” Vliet said. “We didn’t really want them walking off with it.”

Not surprisingly, the bigger the alligator, the harder the bite. The largest, a nearly 12 1/2 -foot behemoth weighing 665 pounds named Hercules, bit down with a more than a ton of force – 2,125 pounds, to be exact, or nearly as much force as the weight of a small sedan.

That’s more forceful than all living animals measured, Vliet said.

The lion, for example, has a bite force of about 940 pounds, slightly less than the hyena’s roughly 1,000 pounds. The only shark tested, the dusky shark, achieves about 330 pounds, while a common dog, the Labrador, bites at a mere 125 pounds or so.

Anyone ever jawed by a toddler might judge the strength of the human bite force to be near infinite. But people bite at a maximum force of about 170 pounds, just one-thirteenth the strength of a large gator.

Vliet said Tyrannosaurus rex may have bitten with a force of some 3,300 pounds. However, smaller theropod dinosaurs, or bipedal carnivorous dinosaurs, may have bitten with a force of no more than 450 pounds.

Vliet, who studies alligator ecology, said he’s interested in alligators’ bite force because their varied diet often includes turtles. To consume the animals, alligators have to crack their shells, which raises the question for Vliet of much force is involved.

Erickson said he studies the feeding behavior of dinosaurs and other extinct reptiles. The alligator, he said, provides a good living example of how these animals were put together.

“Crocodilians, such as the alligator, are the closest living relatives to dinosaurs,” Erickson said. “Their jaws, teeth and musculature provide an excellent model for the feeding biomechanics of these extinct beasts.”

Alligators, for their part, seem to have an innate understanding of their mouths’ crushing potential, Vliet said. When eating turtles, they often maneuver the animals to the back of their mouths, then squeeze them like jawbreakers until, in Vliet’s words, they either “pop” the shell or abandon the effort.

“You’ll occasionally see them with a turtle, and they’ll work on it for a long time, like 15 to 20 minutes,” he said. “They’ll eventually either crush the thing or spit it out.”

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