Speedy, 500-meter-wide asteroid to pass near Earth on Nov. 29

A study led by Ken Shushimada from DePaul University suggests that megalodon sharks could have grown up to 15 meters, much larger than previous estimates of 10 meters. This new estimate is based on a more accurate equation considering favorable water temperatures. The study, published in Historical Biology, also explores how intrauterine cannibalism, a behavior seen in modern sharks, could have contributed to the megalodon's massive size. By eating their siblings in the womb, megalodons could have emerged larger, increasing their survival chances. These adaptations, combined with favorable conditions, allowed them to grow to unparalleled sizes.

What was the previous estimate of the megalodon's length based on fossilized teeth?

What factors are mentioned that could have allowed megalodons to grow to their gigantic lengths?