When looking at ancient animals’ size scientists only have fossil evidence to work from, so scaling up the tissue mass of a giant shark from only the teeth that remain is a tricky puzzle. Now, a new study published in the journal Scientific Reports believes it’s cracked the code to the true size of the mighty megalodon, which they predict was 16 meters (52 feet) long with fins the size of an adult human.
Otodus megalodon was one of the ocean’s most voracious predators when it lived from 23 to around 3 million years ago. Its serrated teeth tell us that it fed on meat, most likely the flesh of whales, large fish, and other sharks. Being so enormous means their necessary calorie intake was very high, making large prey a necessity in their diet. There has even been fossil evidence of megalodon teeth still lodged in the bones of ancient whales, likely having snapped off during an attack.
Guessing the diet of an animal from the shape of its teeth is one leap but imagining an animal’s complete body size from their dentition alone is no mean feat. To come to their estimations, the team from Swansea University and the University of Bristol, both UK, used mathematical models to narrow down the proportions of the megalodon. They were able to compare its body size to that of five shark species living today that share physiological characteristics and work out its size during different periods of its life.
"Megalodon is not a direct ancestor of the Great White but is equally related to other macropredatory sharks such as the Makos, Salmon shark and Porbeagle shark, as well as the Great white,” said shark expert Dr Catalina Pimiento in a statement. “We pooled detailed measurements of all five to make predictions about Megalodon."
They looked at changes in the extant species’ proportions as they aged to get an idea of how megalodon’s size might change throughout its life in a similar way to how humans grow from babies to children and eventually settle in their adult form. They were relieved however to discover that these modern species exhibit a simple growth pattern, essentially starting life as small adults and growing large but maintaining their composition throughout their lives. This meant they could essentially scale up the growth curve of the modern sharks to predict the size of the megalodon, landing at an adult length of around 16 meters.
These enormous sharks were more than twice the size of modern great whites, with a dorsal fin around 1.62 meters (5.3 feet) in height, around the height of an adult human. Their huge heads were around 4.6 meters (15 feet) in length and clocked a bite force of more than 10 tons, a harrowing thought in the context that today’s great white’s clock a measly 2-ton bite force. In piecing together the life and size of this ancient ocean giant it's hoped scientists can better understand why it went extinct, potentially contributing towards the survival of today's threatened marine species.