New research published in the journal Biology Letters has, for the first time, been able to confirm that the mighty megalodon, Otodus megalodon, relied on nesting waters, which were widespread temporally as well as geographically. These safe havens for young megalodons provided food and a degree of protection from the greatest predators of the time, reducing early mortality and helping to maintain viable adult populations. The researchers suggest that a reduction in suitable nursing grounds could have played a pivotal role in the eventual demise of one of natural history’s greatest predators more than 3.5 million years ago.
The study authors looked at 25 megalodon teeth from the Reverté and Vidal regions in Tarragona, Spain, from which they were able to estimate full body size by inputting the fossil’s measurements into a mathematical model. Their findings revealed that the teeth from these sights belonged to younger sharks that were around 4 meters (13 feet) in length and older juvenile sharks that were around 11 meters (36 feet) in length. A recent study used this same modeling and found that an adult would have been 16 meters (52 feet) long with fins the size of an adult human. The enormous difference in size between this adult and those found in Tarragona demonstrates that these sharks were not yet fully grown.
The site at Tarragona dates back to the Miocene epoch, and the researchers compared the teeth found here to those found at five known megalodon nursery sites including in the Atlantic, Caribbean, and Pacific basins. Fossilized teeth were used to predict total body size in all cases and analyses of these showed that all in all, the megalodon nursing waters stretched from the Langhian (middle Miocene) geologic timescale to the Zanclean (early Pliocene) demonstrating an enormous reach across both space and time.
The study is the first of its kind to confirm the enduring nature of megalodon nurseries, demonstrating that they played as vital a role for these ancient apex predators as they do for extant sharks roaming the oceans today. The researchers suggest that therefore, the availability of suitable nurseries may have been the deciding factor in the species’ ultimate demise as without safe waters for juveniles to develop into viable adults the populations were unable to secure a future for megalodon. Good for keen sailors but a sad reality for massive shark enthusiasts.
“These results reveal, for the first time, that nursery areas were commonly used by O. megalodon over large temporal and spatial scales, reducing early mortality and playing a key role in maintaining viable adult populations,” wrote the study authors. “Ultimately, the presumed reliance of O. megalodon on the presence of suitable nursery grounds might have also been determinant in the demise of this iconic top predatory shark.”