In a new 3D modeling study published this week in the journal Science Advances, we show that the extinct giant shark Otodus megalodon is a true circumnavigation super predator.
It is able to cross long distances in a short period of time and eat the largest super predator whale in modern life in five bites. It could have swallowed a great white shark.
The largest shark ever
The megalodon is the largest shark ever built, and it has been around for a long time — from about 23 million years ago to 2.6 million years ago. Once upon a time, it was common: fossilized teeth were found on every continent except Antarctica. If you encounter them, these teeth are not difficult to identify because they can be up to 18 cm long.
Why this terrible predator went extinct remains a mystery. This could be related to global cooling or competition from other predators such as orcas (killer whales). This is just one of many outstanding issues.
One thing we can be sure of is that megalodons are huge — but exactly how big they are is still a point of debate among scientists, as previous estimates were actually based on fragmented debris.
Its size is really important because it helps us explain its biology — the kinds of prey an animal can kill and eat, how much food it needs to survive, and how fast it travels.
Dietary issues are particularly important because they determine the role of animals and their impact on ecosystems. Historically, many believed that megalodons would prey on very large prey, including large whales.
But recently it has been suggested that it may not be the super predator it cracked, concluding that it focuses on smaller prey such as seals, dolphins and small whales between 2 and 7 meters in length. If correct, this would have a major impact on our understanding of how marine ecosystems functioned at the time.
Our new model now shows that it does prefer larger prey.
I've always been interested in megalodons. Back in 2007, I published a paper with colleagues in which we built a computer simulation to predict its bite force.
Our estimate — 18 tons of car crushing — depends on the hypothetical weight of the animal, so I was pleased when colleagues from overseas asked me to help try to develop a more accurate model of the whole shark. From there, we can determine its size more reliably.
Previous estimates of megalodon weight and proportion were largely extrapolated from data from individual vertebrae, leaving a large margin of error. Others are based on direct comparisons with living great white sharks; However, it is now clear that the two are not closely related.
In our new study, our estimates are based on a 3D modeling of the most complete known specimen, represented by the most complete spine preserved in a Belgian museum. We quantified its total length, weight, and clearance size from the complete digital model.
Finally, we estimated the megalodon's cruising speed, stomach capacity, daily energy requirements, and the speed at which it might encounter prey.
We concluded that this particular megalodon shark is about 16 meters long and weighs more than 61 tons. This is much larger than the recent estimate of 48 tons.
According to other isolated vertebral fossils, it may be the largest megalodon growing to 20 meters long. We further determined that the Belgian specimen had a maximum mouth of about 1.8 m and its stomach could hold 9.5 m3 of food.
This suggests that it may have taken only five bites to completely eat the largest killer whale (about 8 meters) in existence.
Suppose it took just three bites to devour another iconic super predator, the T-Rex. As for the great white shark, the megalodon may have swallowed a large shark.
Our findings suggest that megalodon sharks can cruise comfortably at speeds of more than 5 km/h. That's much faster than the largest live fish, filter-feeding whale sharks, and even great white sharks about 3 kilometers per hour. Megalodons are the largest sharks ever built and require a lot of food to survive.
This super predator, which crosses the ocean, can travel long distances in a short period of time, increasing the speed at which prey encounters and enabling it to move quickly to take advantage of seasonal changes in prey abundance.
Our energy analysis suggests that if a large killer whale had been eaten for breakfast, the megalodon shark might have flown about 7,000 kilometers before it would need to eat again.
In short, our findings suggest that the megalodon is indeed its super predator, and even more.
No creature, no matter how big or small, can escape the mouth of this super shark. Its extinction may have had a huge knock-on effect on the marine environment of the time.