Megalodon sharks, which became extinct around 3 million years ago, were apex predators at the greatest trophic level yet observed.
They were three times longer than contemporary great white sharks.
To determine the trophic levels of the ancient predators, scientists examined nitrogen traces trapped in shark tooth enamel.
Prehistoric history of megalodon
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The oldest megalodon fossils, identified as Otodus megalodon (sometimes called Carcharodon or Carcharocles megalodon), date to 20 million years ago, as per the Natural History Museum.
The gigantic shark ruled the waters for the following 13 million years before going extinct only 3.6 million years ago.
Three times longer than the biggest great white shark ever documented, estimates put its maximum length at between 15 and 18 meters.
Megalodon would have likely devoured whale flesh, huge fish, and maybe other sharks with its massive serrated teeth.
Large prey is necessary since an animal of its size has to consume a lot of food. This would have encompassed creatures of all sizes, from dolphins to humpback whales.
Whale bones preserved in fossil form provide more proof of the megalodon's eating habits.
Megalodon teeth's cut marks are engraved into the surface of several of them.
Some even have the ends of teeth that were snapped off during a feeding frenzy that happened millions of years ago and lodged in the bone.
Megatooth sharks are named like so because of their enormous teeth, which can grow to be as large as a human hand, as per ScienceDaily.
The group comprises numerous closely related species as well as Megalodon, the biggest shark to have ever lived.
Megatooth sharks emerged after the dinosaurs were extinct and controlled the seas until about 3 million years ago, even though sharks of various kinds have existed for more than 400 million years, dating back to long before the dinosaurs.
According to Emma Kast, a 2019 geology Ph.D. graduate and the study's primary author, they typically conceive of the biggest creatures as filter feeders or herbivores, not predators, including blue whales, whale sharks, even elephants, and diplodocuses.
If Megalodon existed in the present seas, it would fundamentally alter how people interact with the marine environment, according to her advisor Danny Sigman, the Dusenbury Professor of Geological and Geophysical Sciences at Princeton.
Megalodon and some of its ancestors must have consumed other predators and predators-of-predators in a complex food web, according to a team of Princeton researchers, who have now found convincing evidence that they were at the very top of the prehistoric food chain, or what scientists refer to as the highest "trophic level."
Very few bones have survived with teeth marks that indicate they were nibbled on by a large shark; without a time machine, it is difficult to reproduce the food chains of ancient animals.
The fact that the nitrogen isotope levels in a creature's cells tell whether it is at the top, middle, or bottom of a food chain has helped Sigman and his colleagues spend decades inventing alternative techniques.
According to Sigman, the goal of the research team is to find organic stuff, including nitrogen, that is chemically fresh yet physically preserved in far-off geologic creatures.
A few species at the base of the food chain have mastered the art of converting nitrogen from the air, including plants, algae, and other species.
The nitrogen that they ingest is subsequently incorporated into the bodies of the organisms that consume them, and crucially, they preferentially excrete more of the lighter isotope of nitrogen, N-14, than its heavier relative, N-15.
In other words, as you move up the food chain, N-15 increases than N-14.
This method has been utilized by other researchers on organisms from the recent past, within the last 10 to 15 thousand years, but older animals haven't had enough nitrogen remaining to quantify until now.
Shark teeth are so common and well-preserved that nitrogen signatures in enamel may be used to gauge position in the food chain.
Nitrous oxide must be extracted, purified, concentrated, and delivered to a specialized stable isotope ratio mass spectrometer using specially designed, automated equipment for this study.
