Jan. 9, 2009 -- A big body helps, but the primary predictor for how hard a shark can bite is the width of its head, according to a new study that measured biting force in several shark species.
In descending order, the top five hardest-biting sharks, based on this study and prior research, are: the great white, great hammerhead, bull, blacktip and horn sharks.
The largest great white on record, which measured around 24 feet long, would've had a bite force of 9,320 Newton at the tip of its jaws and 18,216 N at the back of its jaws, where the leverage is higher.
"A key finding over the years has been that pound-for-pound, sharks don't bite overly hard for their body size compared to other animals," lead author Daniel Huber told Discovery News.
Related Content:
"However, their large body sizes make the overall magnitude of bite force so great that the pound-for-pound issue goes out the window," added Huber, who is an assistant professor of biology at the University of Tampa.
For the new study, he and his team took measurements of length, body mass, head height and head width for 10 variously sized sharks, with the blackbelly lantern shark being the smallest studied and the great hammerhead being the largest.
The researchers gathered data about each species' bite force, either from other studies or by calculating it based on muscle and jaw geometry. The scientists determined which shark characteristics were most closely linked to bite force.
The findings are published in the latest issue of Biological and Biochemical Zoology.
Head width was found to be the best predictor of bite force across all species. A hard diet, consisting of foods like sea turtles, large sea birds and even other sharks, was also found to predict how hard a shark could chomp.
The researchers were surprised to learn, however, that the hardest biters also seemed to have the sharpest teeth. This seemed counterintuitive, since when a shark's jaws clamp together into hard food, the eater could crack its own teeth. Also, greater biting force would appear to eliminate the need for such pointy teeth.
Instead, the scientists discovered that many hard-biting sharks have teeth that overlay each other, "kind of like roof shingles on a house," Huber said. "This reinforces them and helps to distribute stresses throughout all of the teeth."
Sharks can also quickly replace any missing teeth.
Big sharks often have big heads, but the head doesn't always match up with body size. Filter feeders, like whale and basking sharks, probably have relatively low biting forces when body size is accounted for.
Certain other sharks, such as the mako, have necessarily narrower heads in order to cruise streamlined through the open ocean. Bull sharks, on the other hand, have huge heads relative to their bodies, as do great whites.
"Nature has endowed this carnivore (the great white) with more than enough bite force to eat large and potentially dangerous prey," said Steve Wroe of the University of New South Wales, who led the other study on this particular shark.
The great white's champion biter title could soon be challenged, however, as no one has released findings yet concerning the bite force of the wide-headed tiger shark, which Huber is now studying.
Related Links:
our sites
video
mobile
shop
stay connected
corporate
