Sharks are famous for their teeth, rows and rows of serrated cutting tools lining the creature's deadly maw. One chomp from those pearly whites can tear tender flesh wide open. But how deadly are they exactly?
To find out, a team of researchers -- Professor Adam P. Summers from the University of Washington's Friday Harbor Laboratories and Cornell students Katherine Corn and Stacy Farina -- decided to build a reciprocating power saw using a bunch of shark teeth.
This is because sharks don't just bite down when they sink their teeth into prey -- they shake their heads, the sharp edges of their teeth rending flesh.
To learn more about the effect this has, the team mounted a variety of teeth from different shark species on to different sawblades using epoxy: a tiger shark, a sandbar shark, a silky shark and a sixgill shark. Then the team tested the toothy tools -- dubbed "Jawzall" -- on dead salmon, videotaping the results.
What they found was that the tiger shark's teeth are the most deadly of those tested, breaking the salmon's spine in six cuts; the tiger shark often feasts on difficult prey, such as sea turtles and crustaceans, so deadly teeth are a requirement.
The least deadly was the sixgill shark, but, since it feasts on carrion, it doesn't have a strong need to be able to kill prey.
The other thing the team found is that the shark's teeth dull quite quickly: after the first 12 cuts, the sawblade was only cutting seven percent of the tissue it cut in the first six cuts. It could be partially for this reason, they hypothesised, that sharks' teeth replenish so quickly.
Probably just as well we don't have a shark tooth saw in our tool shed, then.