When a group of researchers decided to find out just how deadly a shark's teeth could be, they decided to do the most sensible thing any good scientist would do: build a shark teeth saw in the name of experimenting for science.
Biologists from the University of Washington and Cornell University have put together the world's most badass power-saw by gluing four to 10 teeth from a tiger shark, sandbar shark, silky shark, and sixgill shark to the blade of a Sawzall reciprocating saw. Named the Jawzall, the shark teeth power-saw was used to cut through the meat of dead salmon as the researchers recorded the results on video.
Most of us know just how dangerous a shark's sharp bite can be, thanks largely to Jaws, but many sharks shake their head when they clamp down on their prey. This way the shark's rows of serrated teeth lining its jaws tear away at its victim's flesh. The researchers believe the back-and-forth cutting motion of the power-saw mimics how sharks rip their poor dinner apart.
Sharing the results of their little experiment at the annual meeting of the Society for Integrative and Comparative Biology, Cornell undergraduate Katherine Corn said the tiger shark's teeth was the most deadly of all; it was able to break the salmon's spine in six cuts. This shouldn't be so surprising, as the tiger shark uses its sharply serrated teeth, each with a large notch, to feed on crustaceans and turtles as well as other soft-bodied preys.
On the other hand, the sixgill shark has large, coarsely serrated teeth that showed the poorest performance on the Jawzall. The sixgill shark feeds on carrion, so it doesn't need teeth as sharp as the tiger shark's.
"There actually is a significant effect of tooth morphology. That's really striking," Corn told Popular Science. "We may be able to extrapolate factors about feeding ecology from tooth morphology."
The researchers also found out that the shark's teeth dulled quickly. According to Corn, the Jawzall became seven percent less effective on its twelfth cut compared to its performance during the first six cuts. She believes this partially explains why sharks replace their teeth quickly.
Corn, who is taking up biologist Adam Summers' class at the University of Washington's Friday Harbor Laboratories, said she volunteered for the task when her professor asked who was interested in gluing shark's teeth to a saw. Part of her duties was to defrost the jaw of a sixgill shark that washed up on Friday Harbor two years ago.
"It was a big shark," Corn said. "Those jaws were magnificent."
Also part of the group is Stacy Farina, a graduate student at Cornell University.
The video of the shark teeth saw in action can be watched on ScienceMag.com.
