What Bites Harder Than A T. rex?

No, not The View. Not even Matt Nisbet.

The new crown for most powerful bite force appears to belong to the Megalodon, an extinct species of gargantuan shark that grew to more than 50 feet long and weighed up to 110 tons. Early whales must have breathed a sigh of relief when Megalodon became extinct about 1.5 million years ago. Estimates suggest the toothy terror was at least 30 times as heavy as the largest of its living relatives, the Great White shark.

Technically speaking, megalodon (meaning "big tooth") is the species name for this juggernaut of a shark. But it's the preferred shorthand, given that a bit of a naming squabble is still playing-out over the genus name. When I was but a wee, aspiring marine bio lad, the shark was commonly called Carcharodon megalodon. The genus Carcharodon, meaning "sharp or jagged tooth" also happens to be the genus of the extant Great White shark (Carcharodon carcharias). Due to almost identical shape and arrangement of the teeth of the Great White shark and fossilized teeth of the megalodon, famed Harvard paleontologist and creationist Louis Agassiz proposed Carcharodon as the genus for megalodon as well.

But appearances may be deceiving and convergent evolution can play tricks on the eye, claim a growing consensus of vertebrate paleontologists. Kevin Nyberg (formerly at Duke University) and others say the similarity is merely superficial and that modern Great White's originated from an extinct group of Mako sharks and not from the megatoothed giants. Some paleontologists have proposed the genus, Carcharocles, as a more accurate lineage suggesting that the direct ancestor of the megalodon shark is an ancient shark called Otodus obliquus, which lived during the Paleocene and Eocene epochs. O. obliquus gave rise to Carcharocles aksuaticus, and then a whole slew of Carcharocles intermediaries on the way to Carcharocles megalodon.

Confused yet? Classification wonks can head here if you absolutely must know more about the megalodon naming debate. But back to bite strength.

In a report published last week by the University of New South Wales in Sydney, Australia, researchers suspected that previously published values for maximum bite force of Great White sharks was greatly underestimated. They discovered that previous bite force tests were performed on small bait prey or using materials which likely caused the sharks to "hold back" on full bite delivery. Correcting for this in their new bite tests, researchers also performed elaborate CAT scans (above image) and digital recreations of a great white shark bite musculature (left). They found that the largest great whites have an astounding bite force of up to 2 tons.

"That is more than three times that of the bite of an African lion and more than 20 times that of a human. It's the biggest bite force known for any living animal so far, although it's certainly possible that the killer whale or possibly the larger crocodiles have more powerful bites," reported Stephen Wroe, a biomechanist and paleontologist at the University of New South Wales.

Based on presumed similarities of jaw mechanics, researchers hypothesized that megalodon exerted a bite force six to ten times stronger than the Great White. That surpasses the estimated 3.1 metric ton bite force of Tyrannosaurus rex by a good stretch.

Wroe and his colleagues will detail their findings in a forthcoming issue of the Journal of Zoology.