Photo: Wiki Commons
You might be surprised to learn that the shark with the strongest bite is not the great white, the tiger shark or even the great hammerhead. Rather, it's the more modestly-sized bull shark, according to BBC Nature.
While it's true that the world's largest predatory sharks typically have very strong bites, bite strength is not a perfect scale from largest to smallest. Bull sharks aren't quite so large as some other species, but you still wouldn't want to encounter one wading around in murky water. They can grow to formidable sizes, and are infamous man-eaters. Females, which are a bit larger than males, average 2.4 m (7.9 ft) long and typically weigh 130 kg (290 lb). Even so, researchers were surprised to learn that it was the bull shark that delivered the most whopping chomp.
Maria Habegger of the University of South Florida in Tampa and colleagues, recorded the bite force of 13 species of shark and their close relatives for the study. The smallest species studied was the ratfish, an evolutionary cousin of sharks, and the largest was the great white.
"Sometimes size is misleading. Although larger size sharks will exert higher values of bite force, the relative value of bite force is what matters, pound per pound how strong is the bite?," said Habegger.
Bull sharks were shown to bite with a force measuring 6,000N at the back of the jaw and more than 2,000N at the front. That's much more than is needed to slice through skin or snap bone. So why such a strong bite?
Researchers guessed that the strong bite might be necessary to crunch turtle shells, a popular menu item for many of the large predatory sharks. But that still doesn't explain why it's the bull sharks in particular which have the most fearsome bite.
One trait that is unique to bull sharks among the larger shark species is their high tolerance of freshwater. In fact, bull sharks have been known to swim as far up the Mississippi River as Alton, Illinois. They have even been known to jump the rapids of the San Juan River in Nicaragua, almost like salmon.
Researchers therefore hypothesize that their bite strength might have something to do with their occasional freshwater lifestyle.
"In a lower visibility environment catching prey may be more difficult than in open water. So once you get a prey between your jaws, securing it is crucial to not lose your meal," said Habegger.
Their freshwater ways are also a big reason why most experts believe bull sharks are the most dangerous sharks in the world, since they encounter human swimmers in such a wide variety of habitats. Murky river water also means low visibility, so the sharks are more likely to attack due to cases of mistaken identity. In fact, the string of attacks that inspired the movie Jaws along the Jersey Shore in 1916 were probably done by bull sharks, not by a great white like the film depicts.
The fact that bull sharks have now been shown to have the strongest bites will probably only add to their ferocious reputation as the world's most dangerous shark.
By Bryan Nelson