Watch 'Jawzall': A Real Shark Tooth Saw

Ever wonder why shark teeth are so darn good at shearing through meat and bone? Ever think "man, these would make a for a great saw!" when holding some shark teeth? Now that oddly specific dream can be realized with "Jawzall," a new and bizarre pet project out of Cornell University.

Introduced during the annual meeting of the Society for Integrative and Comparative Biology, Jawzall looks exactly as you'd imagine it would: a sawzall power tool that looks to have seen better days, but complete with an impressive shark jaw-like blade at the end of it.

You can watch a video here (via AAAS) of the cleverly named tool, which can be equipped with a wide assortment of shark teeth to cut its way through a slab of chum salmon.

And while it's pretty cool to watch, you might find yourself wondering what the point of it all is for. After all, sharks don't chew exactly like a sawzall cuts, and experts have long figured out how various shark teeth get the job done.

However, if you watch the video closely, the Jawzall is not being held by human hands, but is instead set up in a simple hinged prop, allowing the blade to press and cut into the salmon flesh with the constant force of just its own weight.

The experiment was set up this way because the researchers are far more interested in the rate at which a shark tooth dulls. Sharks are probably notorious among tooth fairies, as some Carcharhinoformes - the largest order of sharks - have even been known to shed and replace a whopping 35,000 teeth in their relatively short lifetimes.

"Our 'bite force' was substantially below that reported for sharks, due to of limitations of our system," Cornell undergraduate Katherine Corn wrote in an abstract.

However, she and her colleagues did notice a significant effect of repeated use on cutting speed.

"After 12 reciprocations, a tooth cut only 7 percent of the tissue it cut on the first 6 reciprocations," Corn added. "This rapid dulling is enhanced by the high speeds at which we are cutting, as the fish tissues appear much stiffer at high strain rates."

This essentially means that the faster a shark chews, the faster its teeth lose their edge and have to be replaced. What's more, the researcher saw no notable difference between various model tooth shapes from four different shark species, meaning that chomping speed is likely the primary driver of dulling and replacement.

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