Extinct Megalodon would have been terrifying even from the point of view of someone on a midsized yacht, as this artist's portrayal suggests. (Image courtesy Steve Alten/Montage Marketing).

The great white shark has the might­i­est bite of any liv­ing spe­cies known, a study has found—but its ex­tinct rel­a­tive “Big Tooth” may take the prize for hard­est bite in Earth’s his­to­ry.

The an­cient beast is thought to have in­flict­ed hor­ri­fic deaths on large whales, by first bit­ing off their tails and flip­pers and turn­ing the huge vic­tims into hap­less, drift­ing meals. Re­search­ers from the Uni­ver­s­ity of New South Wales in Aus­tral­ia and oth­er in­sti­tu­tions stud­ied the skull and mus­cle tis­sues of both shark spe­cies. They gen­er­at­ed three-dimensional com­put­er mod­els of the skull of a 2.4-metre (eight-foot) male great white based on X-ray im­ages. 

“Na­ture has en­dowed this car­ni­vore with more than enough bite force to kill and eat large and po­ten­tially dan­ger­ous prey,” said the uni­ver­s­ity’s Steve Wroe. 

“Pound for pound the great whites’ bite is not par­tic­u­larly im­pres­sive, but the sheer size of the an­i­mal means that in ab­so­lute terms it tops the scales. It must al­so be re­mem­bered that its ex­tremely sharp ser­rat­ed teeth re­quire rel­a­tively lit­tle force to drive them through thick skin, fat and mus­cle.”

Us­ing im­ag­ing and anal­y­sis soft­ware and a tech­nique known as fi­nite el­e­ment anal­y­sis, the team re­mod­elled the skull, jaws and mus­cles as hun­dreds of thou­sands of ti­ny dis­crete, but con­nect­ed parts. They then dig­it­ally “crash test­ed” the mod­el to sim­u­late dif­fer­ent sce­na­rios and de­ter­mine the bite force, as well as the com­plex dis­tri­bu­tions of stresses and strains that these forc­es im­pose on the jaws. The find­ings are to ap­pear in the Jour­nal of Zo­ol­o­gy.

The group found that the larg­est great whites have a bite force of up to 1.8 tons—three times that of a large Af­ri­can li­on and more than 20 times that of a hu­man. Al­though shark jaws con­sist of elas­tic car­ti­lage, as op­posed to the bony jaws of most oth­er fish, this did­n’t greatly re­duce the pow­er of the chomp, the re­search­ers said.

Wroe and col­leagues ap­plied the same meth­od to es­ti­mate the bite force of “Big Tooth” or Car­char­o­don mega­lodon, which may have grown to 16 me­tres (52 feet) long and weighed up to 100 ton­s—at least 30 times as heavy as the larg­est liv­ing great whites. They pre­dict it could gen­er­ate be­tween about 11 and 18 tonnes of bite force. 

Even fear­some Ty­ran­no­saur­us rex was no match for this gi­ant, Wroe said. “Es­ti­mates of max­i­mum bite force for T. rex are around 3.1 tonnes, great­er than for a liv­ing white shark, but pu­ny com­pared to Big Tooth.”