The bigtooth, the giant shark that went extinct 3.6 million years ago, wasn’t as gigantic as we thought. A new study, published in the journal Palaeontologia Electronica, shows that it was thinner, and this finding changes scientists’ understanding of its behavior, ancient life in the oceans and why these sharks became extinct.

The megalodon is usually depicted as an oversized monster in science fiction films. Previous studies suggested that it probably reached a length of at least 15 meters and possibly up to 20 meters and compared it to the modern great white shark.

However, it is largely known only from its teeth and vertebrae, a rather incomplete set of data.

A team of 26 scientists from around the world, led by University of California, Riverside biologist Philip Stearns and DePaul University paleobiology professor Kenshu Shimanda, found a discrepancy between two previous publications on the length of the megalodon even though the same specimen was studied .

The scientific team re-examined the fossil record and discovered that the megatooth was thinner and possibly even longer. “It would still have been a formidable predator at the top of the ancient marine food chain, but it would have behaved differently based on this new understanding of its body,” Mr Stearns points out.

It has been theorized that the extinction of the megalodon resulted from the reduction of its prey, however after a revised understanding of its shape, Philip Stearns believes that “there was a combination of factors that led to the extinction and one of them may have been the appearance of the great white shark, which was possibly more agile and this made it an even better predator than the big tooth. This competition for food may have been an important factor in its extinction.”