In 1875, the research vessel HMS Challenger dredged two fossilized Megalodon teeth from the South Pacific seafloor near Tahiti. The teeth were recovered from a depth of about 4,360 meters at a location cataloged as Station 281. They were coated with manganese dioxide, a mineral crust that forms slowly on objects resting on the ocean floor.

In 1959, Vladimir Chernesky, a zoologist at Queen Mary College in London, used the thickness of that coating to estimate how long the teeth had been sitting there. He calculated that one tooth was approximately 11,333 years old and the other approximately 24,206 years old. The results were published in the journal Nature and suggested that Megalodon may have survived into recent human prehistory, contradicting the established fossil record, which indicated the species had gone extinct millions of years earlier.

Chernesky’s calculation depended on an earlier estimate of how quickly manganese dioxide accumulates on the seafloor. That estimate was derived using a radium-based dating method. In 1970, researchers Georgi Belyayev and Leonid Glikman published a rebuttal showing that this growth rate was 20 to 30 times faster than the actual rate, as determined by a more reliable technique called ionium-thorium dating. When corrected, the true age of the teeth stretched back into the millions of years.

Belyayev and Glikman also noted that Megalodon teeth from ocean floor sediment are often found alongside teeth from other extinct shark species, including Carcharodon hastalis, an ancestor of the great white shark, and Parotodus benedeni, sometimes called the false mako. Both species are established markers of the Miocene through Pliocene epochs, roughly 23 million to 2.5 million years ago. The Challenger expedition’s own published catalog confirmed that teeth from these species had been recovered from the same sediment collection as the two disputed Megalodon teeth.

In 2007, the German research vessel Sonne dredged two additional Megalodon teeth from roughly the same region of the Pacific. Researchers dated them using strontium dating, a more precise method that measures isotope ratios absorbed into fossil material from seawater. One tooth was placed at approximately 18 million years old, and the other at approximately 6 million years old. These results independently confirmed the corrected timeline.

One detail that kept the original claim alive was that the Challenger teeth looked unusually white and well preserved, which seemed inconsistent with an age of millions of years. A 1998 study explained this appearance. The manganese dioxide coating had acted as a preservative, slowing the chemical decomposition that typically darkens and weathers fossil material exposed on the ocean floor. The same mineral layer that had misled Chernesky’s dating attempt was also the reason the teeth looked deceptively fresh.

The original claim has continued to circulate in popular retellings for more than 60 years, often without mention of the 1970 correction, the corroborating fossil evidence, or the 2007 strontium dating results. A 2019 article in Cryptozoology Review identified the Challenger teeth story as one of the field’s most persistently repeated and least accurately retold cases, noting that the manganese dioxide dating method is broadly unreliable for shark teeth specifically.

No evidence suggests that Megalodon survived into the modern era. The documented record shows a real scientific error, made in public and corrected in public, followed by independent confirmation using more advanced methods decades later. The Challenger teeth were not unusually young; they were unusually well preserved by the same mineral coating that had originally led to a mistaken age estimate.