Research came out last year that revealed the mighty megalodon was indeed the ocean giant we believed it to be. At around 16 meters (52 feet) long with fins as long as an adult human’s body, they dwarfed other fish in the sea when they were alive. Now, a new study published in the journal Historical Biology has claimed that these ocean giants’ progeny were also giants in their own way, making their first few tail swishes in the open ocean at a size already larger than most adult humans.
The study was investigating the growth pattern and life expectancy of megalodon, Otodus megalodon, to shed light on their reproductive biology. "As one of the largest carnivores that ever existed on Earth, deciphering such growth parameters of O. megalodon is critical to understand the role large carnivores play in the context of the evolution of marine ecosystems,” wrote paleobiologist at DePaul University in Chicago and lead author of the study Dr Kenshu Shimada in a statement.
Using computed tomography (CT) scanning technology, Shimada and colleagues were able to look at 'growth bands' in megalodon vertebral specimens, housed in the Royal Belgian Institute of Natural Sciences in Brussels. These bands are similar to tree rings, with each ring representing another year in the fishes’ lifetime. The results revealed the vertebra of a shark estimated to be nine meters long had 46 bands, meaning it was 46 years old when it died.
This information could be used to back-calculate the shark's body size at birth, which told the researchers that it was a wee bonny megalodon measuring around 2 meters (6.6 feet) when it came into the world. They posit that this suggests Megalodon gave live birth and that these fish were capable of snacking on their siblings while waiting to be born. The sinister practice is known as oophagy or intrauterine cannibalism, and is seen in all extant lamniform sharks, says that study. A famous tale among shark biologists describes the moment a scientist was dissecting a dead female tiger shark who was bitten by a cannibalistic embryo that had survived inside the oviduct. If the findings are correct, it could mean that megalodon babies were the largest ever baby sharks.
Megalodon is a popular species among shark fans, regularly featuring in sci-fi movies such as The Meg. While the fossil record of these apex predators is rich, we still don’t know very much about their biology. This is a common problem in cartilaginous fish, who rarely leave much to be found in the fossil record other than teeth. This is why the discovery of their gigantic vertebrae represents such an exciting opportunity academically speaking, as scientists work to close the gap in our knowledge of these fearsome hunters.