Once an animal is secured, Erickson and Lappin tap the snout, which induces the mouth to open so the researchers can insert the bite bar on the rear teeth. Alligators and crocodiles have nerves in their teeth, and when they feel the bar, they chomp down.
"It is pretty easy to make a judgment regarding motivation—a snap versus a slow close," said Lappin. "Most of the time, the animals clamp down with vigor."
For the largest of the living crocodilians—Alligator mississippiensis, or the American alligator—the researchers recorded a bite with 2,125 pounds (964 kilograms) of force.
"If an American alligator bit you, you would have to be able to bench press a small truck to escape, which explains why you simply can't pull apart an alligator's jaws," said Erickson.
The measured bite force of smaller alligators and crocodiles were basically proportional to their size, said Erickson, which allowed the researchers to scale up and estimate a bite force of 18,000 pounds (8,165 kilograms) for SuperCroc, or about the weight of a Mack Truck.
"SuperCroc is not different from crocodiles alive today, just bigger," said Erickson.
Vliet was not at all surprised by the tremendous bite forces of crocodilians:
"I made crude estimates of bite force years ago on large alligators and knew that the forces were large," he said. "I've also been bitten a few times and know from personal experience that the bites have a tremendous crushing force to them."
Into the Wild
Erickson and his colleagues are now preparing to take their research into the wild to see if they get different results.
An alligator bite provoked by the bite bar, they say, is sort of like the reflex that occurs when a doctor taps a patient's knee with a special hammer; the bite response is the same in gators regardless of location. But wild alligators might be in better shape and thus have stronger bites.
"Wild gators move around a lot, catch live prey, and eat hard prey items like turtles," said Vliet. "So the muscles utilized in biting may be better developed than those of captive alligators. Also, since bone density is influenced by nutrition as well as by muscles acting upon the bone, the bones of the head of wild alligators may be stronger than those of captive animals."
The National Geographic Channel Presents SuperCroc documentary encore presentation is April 6, 2003 at 8 p.m. and 11 p.m. ET/PT and again on April 12, 2003 at 5 p.m. ET/PT. To find out more about this program and about a traveling exhibition of a life-size model of SuperCroc, visit our SuperCroc Web site: Go>>
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