Scientists Discover the World’s Largest, Deepest Whale Graveyard, Where Cetacean Remains Have Been Piling Up for Five Million Years

The massive necropolis, located deep in the southeastern Indian Ocean, is teeming with marine life supported by the whale carcasses, including many suspected new species

Sarah Kuta | Daily Correspondent

June 12, 2026 10:00 a.m.

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More than five million years ago, the body of a beaked whale fell to the ocean floor. Ever since then, whale carcasses have been accumulating nearby, creating what researchers now say is the largest and deepest “whale graveyard” ever found.

Scientists discovered the vast cetacean necropolis in early 2023 while using a submersible to explore the Diamantina Fracture Zone, an underwater valley that plunges to around 23,000 feet below the surface in the Indian Ocean, off the southwest coast of Australia.

During 32 dives that followed, they found a massive whale graveyard extending roughly 750 miles along the sea floor. In the small portion that they surveyed, the team found 476 fossilized whales and five more recently deceased individuals, they report in a study published June 10 in the journal Nature.

The researchers explored only about 0.25 square miles. But based on what they found, they estimate the density of whale remains—consisting of both fossils and more recent carcasses—in the graveyard might be as high as 2,000 individuals per square mile.

Exploring the necropolis felt “profoundly special,” study co-author Peng Zhou, a marine geologist at the Chinese Academy of Sciences, tells New Scientist’s James Woodford. “We were looking at the final resting place of millions of whales … a deep time archive of evolution and deep-sea life. It was humbling and awe-inspiring, and we treated the site with the respect it deserves.”

The expansive graveyard contains carcasses from a mix of cetacean species. Researchers discovered the fossilized remains of an extinct beaked whale called Pterocetus benguelae that dates to some 5.3 million years ago. But they also found present-day whale falls, which suggests carcasses have been accumulating at the site for millions of years.

Whale graveyard discovered 7km under the sea

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The largest skeleton found at the site belonged to a 16-foot-long Antarctic minke whale. Researchers also identified the fossilized skull of a new species they’ve named Pterocetus diamantinae, which “improves our understanding of the evolutionary history of beaked whales and helps clarify how this highly specialized group evolved,” study co-author Giovanni Bianucci, a palaecologist at the University of Pisa in Italy, tells the Australian Broadcasting Corporation’s Peter de Kruijff.

When dead whales sink to the ocean floor, their bodies take a long time to decompose and serve as a source of food for many deep-sea creatures. To that end, scientists discovered numerous critters feeding on and living among the carcasses, including jellyfish, tubeworms, brittle stars and bone-boring worms. Many of them may belong to species that have never been described before, the study authors note.

Why did so many whale carcasses amass here? The scientists aren’t sure, but they have a few ideas.

The site is located within a migratory corridor for several baleen whale species, which have special mouth structures to filter feed, so some of those individuals may have died of natural causes. Members of deep-diving “hunter species” might have perished while pursuing prey, with the exceptionally deep zone “pushing them perilously close to their limits,” Jon Copley, a marine ecologist at the University of Southampton in England who was not involved with the research, tells the Guardian’s Nicola Davis.

Another possibility is that the creatures died farther from the graveyard and their bodies were funneled to the site because of the Diamantina zone’s V-shaped topography. The location might be the underwater equivalent of “terrestrial tar pits or caves that are natural traps where biological remains accumulate over time,” Nick Pyenson, lead curator of fossil marine mammals at Smithsonian’s National Museum of Natural History, who was not involved with the study, tells Live Science’s Chris Simms.

Several factors likely contributed to the skeletons’ preservation. Most of the bones that researchers found came from the snouts of beaked whales, which are “hyper dense, almost like bone armor, which makes them physically resistant to degradation and less palatable to bone borers,” lead author Xiaotong Peng, a marine scientist at the Chinese Academy of Sciences, tells New Scientist.

Additionally, sediment accumulates very slowly in the Diamantina Fracture Zone, and its deep-sea environment is cold and stable. The bones were also covered in a protective crust of minerals, which further inhibited their decay.

“It’s really a combination of bone density, slow burial and mineral coatings that has allowed these bones to escape being eaten for over five million years,” Peng tells New Scientist.

The necropolis discovery is “truly unique,” Stephen J. Godfrey, curator of paleontology at the Calvert Marine Museum in Maryland who was not involved with the research, writes in an accompanying commentary. Although the deep, remote zone is difficult to access, it likely holds “many other exciting finds,” he adds.

“[The] paper reminded me of a trailer for the first in a series of epic movies,” Godfrey writes. “I hope that there will be many more of these blockbusters to come.”

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Sarah Kuta is a writer and editor based in Longmont, Colorado. She covers history, science, travel, food and beverage, sustainability, economics and other topics.