A graveyard of fossilized shark teeth was found nearly 5.3 miles below the Indian Ocean, according to researchers from Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO).
The researchers discovered the teeth in October during a month-long voyage along Indonesia’s southern coast. They had been traveling aboard their 308-foot (94-meter) research vessel, the RV Investigator.
After twenty-six unsuccessful attempts to capture fish for their ongoing biodiversity study, the researchers dropped a trawling net deep into the ocean on the last day of their mission. According to the team’s statement, hundreds of shark teeth were captured and lifted from the dense mud instead—to their amazement.
In speaking of the discovery with Live Science, Dianne Bray, senior collections manager at the Museums Victoria Research Institute, said, “It was our very last sample of the trip before heading back to Australia.”
“I was a little disappointed at first when we hauled up the net because it was filled with mud, and I knew that there wasn’t [sic] going to be many fish specimens,” she said. “And even if there were, they would be rumbled and damaged from all the mud.”
“We tipped the contents out on the deck of the boat, and as we went through everything, we found shark tooth after shark tooth,” Bray recollected. “We were finding teeth from [modern] mako and [great] white sharks, but also fossilized teeth from ancient sharks like the immediate ancestor of the giant megalodon shark.”
Researchers collected 750 teeth
Shark graveyard discovered in the Indian Ocean!
Scientists found more than 750 mineralized shark teeth 5km underwater.
Some teeth were millions of years old. pic.twitter.com/5OipA5xQSm
— Khalil A. Cassimally (@notscientific) December 15, 2022
Researchers collected around 750 teeth, the smallest being 0.39 inches (one centimeter) and the largest, a megalodon ancestral tooth, measuring four inches (ten centimeters) in length.
Due to time spent on the ocean floor, the teeth developed black manganese nodules, as observed by researchers. Aside from this, however, every tooth appeared to be in good condition.
“It’s quite remarkable,” Bray said. “The teeth weren’t weathered, rumbled, or tumbled. Bacteria consumed all of the organic matter from the teeth, and the roots were gone, but otherwise, the enamel was left” intact.
According to Bray, senior collections manager at the Museums Victoria Research Institute, the researchers aren’t completely certain why there were so many shark teeth in this particular part of the water, but they do not believe that hundreds of sharks could have possibly died in that region.
Gareth J. Fraser, lecturer in Evolutionary Developmental Biology at the University of Sheffield in the United Kingdom, reported on the matter in The Conversation. He stated that unlike humans who are born with one set of baby teeth that are later replaced by adult teeth, sharks have an unending supply of teeth replaced “like a conveyor belt” throughout their lifetime.
A community of ancient sharks
It has been determined that the most plausible explanation for the accumulation of shark teeth in the area is that an ancient shark community lived in this region of the Indian Ocean.
“The teeth were found on an abyssal plain and not out in the open ocean,” Bray said. “This area was part of an ancient reef covered with seamounts, and we think a community of sharks swam around this area long ago.”
It is likely that the sharks lost their worn-out teeth while swimming. According to Bray, the shark teeth just “scraped the surface” of what was actually buried there at such great depths. Hence, it is truly remarkable that they were discovered in the aforementioned spot in the first place.