Big Baby Sharks

Otodus megalodon was one of the largest carnvivores ever seen on this planet. It roamed the oceans 15 to 3.6 million years ago, snapping up marine mammals for a snack. Being a cartilagenous shark, only its enormous teeth tend to have been preserved. A study carried out at Stockton and William Patterson Universities, in New Jersey, however, did a CT scan of a rare preserved vertebra of a megalodon (https://www.theguardian.com/environment/2021/jan/11/baby-shark-newborn-megalodons-larger-than-humans-scientists-say). They found what appeared to be growth rings (like those on a tree). These were used to extrapolate back to the size of the baby shark, when it was 'born'. Sharks, that don't lay eggs (so-called 'mermaid's purses'), are actually ovoviviparous. The eggs are retained in the female's body, without a placenta, and probably eat their siblings to survive and grow. So release from 'mummy shark' is not actually birth. The scientists calculated that the baby sharks were 2 metres in length (my height), at the time of their emergence. This would mean they were fairly immune from attack by anything else, at this time, and free to roam the seas. Why they actually died out is something of a mystery.