A six-meter shark starved an 18-meter giant shark millions of years ago
New research analyzing the fossilized teeth of an extinct shark known as the megalodon has established that it disappeared because a much smaller shark deprived it of prey and starved it to death. David, once again, defeated Goliath.
The story of David against Goliath has been repeated in the oceans, according to the results of research by the Max Planck Institute for Evolutionary Anthropology and published in the journal Nature Communications.
The legend contained in the Book of Samuel of the Hebrew Bible tells that the Philistine giant Goliath was killed in single combat by a young man named David.
Since then, the legend has become the benchmark for a competition in which a smaller, weaker opponent meets and takes down a much larger, stronger opponent.
What the German researchers tell in their study can be considered a new episode, always repeated throughout history, of this legend, whose origin dates back to the 7th century BC. c.
unequal duel
The Goliath of this evolutionary epic was a huge shark, now extinct, which terrorized the seas between 23 and 3.6 million years ago: it measured up to 18 meters in length and weighed about 100 tons. It was scientifically called Otodus megalodon.
The David is a shark that still lives among us, the white shark, which can reach a length of six meters at most. New research has concluded that this shark wiped out the giant megalodon.
He considers that his disappearance could be the result of the competition that the white shark did to megalodon in the search for food.
He has reached this conclusion by analyzing the fossilized teeth of the gigantic shark, of whose existence there are hardly any traces: although their skeletons have disappeared, their teeth have survived as fossils.
Shark teeth
In this study, the researchers analyzed the stable isotope ratios of zinc in modern shark teeth and in fossils from around the world, including megalodon teeth and modern great white sharks.
Zinc stable isotope analysis of dental enamel, the highly mineralized part of teeth, revealed that dietary-related zinc isotope signatures are preserved in the highly mineralized enameled crown of fossil shark teeth.
As the zinc integrated in the shark’s tooth comes from its diet, it allows us to find out what trophic level had acquired at a certain point in his life. The trophic level refers to the classification of species according to the way in which they obtain their food.
What the researchers were able to conclude from their chemical analyzes is that both white sharks and megalodons ate the same prey.
And this finding has led them to the conclusion that the little white shark ended up depriving the megalodon of prey, causing its total extinction. Once again, David had cleverly defeated Goliath.
big jaws
The megalodon is considered one of the largest and most powerful predators in the history of vertebrates. Most estimates of its size are extrapolated from the teeth.
Estimates suggest that its large jaws could exert a bite force of up to 110,000 to 180,000 newtons (25,000 to 40,000 lbf).
Fossil remains indicate that this giant shark had a cosmopolitan distribution, with breeding areas in warm coastal areas. It probably had a very important influence on the structure of the marine communities of its time, until another much more modest shark starved it to death.
Previous estimates have suggested that since megalodons preferred warmer waters, surely ocean cooling associated with the onset of ice ages, together with lower sea levels and the resulting loss of suitable breeding areas, might also have contributed to its extinction.
Reference
Trophic position of Otodus megalodon and great white sharks through time revealed by zinc isotopes. Jeremy McCormack et al. Nature Communications, volume 13, Article number: 2980 (2022). DOI :https://doi.org/10.1038/s41467-022-30528-9