Megatooth sharks, or Megalodons as they are more commonly known, once roamed the world’s oceans over three million years ago. Enormous in nature, it is no surprise that their babies were born larger than adult humans. Most likely because they ate their siblings in the womb.
Researchers at DePaul University in Chicago recently uncovered this unsettling fact after x-raying the vertebrae of a 15cm wide, nine-metre long fossilised Megalodon. Working backwards, they estimated that it would have been about two metres (6.5 ft) long when it was born. It is already known that adult megalodons could grow up to 15 metres in length. Their findings were published online in the journal Historical Biology.
The scan also revealed that the fossil has 46 growth bands, which scientists believe reveal the animal’s age in years, much like the rings of a tree stump.
The megalodon is considered among the largest carnivores in Earth’s history, and the sheer size of its newborns suggests that they fed on the unhatched eggs of their siblings in the womb. Those that ate their siblings were born larger and stronger, standing a better chance of surviving against predators.
“The new study is really the first of its kind for megalodon that has given us good insight into its size at birth, reproductive mode and growth pattern,” said Kenshu Shimada, a professor of palaeobiology who led the research.
“Based on the sizes of the smallest known megalodon teeth, I had a hunch that the size at birth may be around two to 2.5 metres.”
Researchers also posit that the fish had a steady growth rate of over 16cm a year until about the age of 46. Typically, megalodons lived to at least 88.