'If you can bench press a car, you are good to go': Inside the incredible bite-force of crocodiles

In this adapted extract from "Bite: An Incisive History of Teeth, from Hagfish to Humans" (Algonquin Books, 2024), author and vertebrates zoologist Bill Schutt investigates the extraordinary bite force of living crocodilians, as well as their formidable predecessors, Deinosuchus and Sarcosuchus — the "most forceful biters in History."

"There are no 'pretty good' crocodilian researchers, Gregory Erickson quipped. “In my business, if you're not very good, you're missing an arm or something." Erickson, a professor of anatomy and vertebrate paleobiology at Florida State University, also emphasized that it takes a team of experienced handlers to secure the larger specimens. "We always have four or five people who really know their stuff."

Though Erickson has a range of research interests, I’d contacted him because of his research into the biting behavior of alligators, crocodiles and their relatives,

Once strapped down, a tap on the snout usually causes the test subject to open its mouth, after which the bite bar is placed onto the rear teeth. That's because the laws of physics dictate that a measurement taken closest to the jaw joint will provide the greatest bite force.

This placement also stimulates something akin to the knee-jerk reaction you might have experienced while being examined by a rubber-mallet-wielding physician. Here, though, the reflexive response by the crocodilian is to chomp down on the bite bar with full force. Although Erickson's first experiments centered on alligators (which makes perfect sense, given his Florida location), eventually he and his coworkers were able to obtain bite-force data on all 23 species of extant crocodilians, a group that includes crocodiles, alligators, caimans (alligator relatives from Central and South America), and gharials (narrow-snouted piscivores).

"We try to do three to five [individuals] of each species," Erickson said, emphasizing that this practice increased the chances of obtaining a true indication of the bite forces for that species. Ultimately, the largest Animals they measured were several 17-foot (5.2 meters) saltwater crocodiles (Crocodylus porosus), which, along with the Nile crocodile (Crocodylus niloticus), happen to be the species involved in the greatest number of fatal and nonfatal attacks on humans.

Erickson and his fellow researchers were interested in determining how bite forces varied between species. Before their study, there had been several hypotheses predicting that bite forces in crocodilians would vary depending on factors like tooth shape, or the length or width of the jaw — variables that were readily observable traits commonly used to identify the species in question.