Newborn megalodons were larger than humans, researchers say

Enormous megatooth sharks, or megalodons, gave birth to babies larger than most adult humans, researchers have said.

Formally known as Otodus megalodon, these sharks patrolled the world’s oceans more than three million years ago.

The gigantic fish rank among the largest carnivores in the history of life on Earth. Scientists have uncovered plenty of fossils, but megalodon biology is poorly understood because the teeth are often all that remains of the cartilaginous creatures.

Scientists discovered this when they X-rayed the vertebra of a fossilised megalodon and found that it must have been about two metres (6.5 ft) long when it was born. Their remnants have revealed that adults grew to more than 15 metres in length, but until now their size at birth was unclear.

Also, scientists took CT scans of a rare megalodon vertebra kept in a collection at the Royal Belgian Institute of Natural Sciences in Brussels. The 15cm (6in) wide fossil was estimated to come from a megalodon nine-metres long.

Scientists have believed growth bands on an animal's body indicate their age in years, much as tree rings reveal annual growth in trees. In this particular case, the scans revealed 46 growth bands in the fossil. The researchers hence estimated that the newborn megalodon reached two metres from nose to tail.

They concluded the typical lifespan of the species was at least 88 years.