World's deepest graveyard discovered in Indian Ocean. It belongs to giant whales

Scientists have identified a vast whale graveyard and active whale-fall sites in the southeastern Indian Ocean. The find links millions of years of whale remains with thriving deep-sea life and fresh clues to whale evolution.

In Short

• Researchers mapped 485 fossil sites and five active whale-fall ecosystems
• Some remains date back 5.3 million years to the Early Pliocene
• Bone-eating worms and brittle stars thrived around these nutrient-rich remains

Scientists have uncovered what is believed to be the world's deepest and most extensive whale graveyard in the southeastern Indian Ocean, a remarkable discovery that is shedding new light on whale evolution and the hidden ecosystems of the deep sea.

The finding, published in the journal Nature, was made by a team of researchers from the Chinese Academy of Sciences, working alongside scientists from the University of Pisa and Earth Sciences New Zealand. The site lies within the Diamantina Fracture Zone, a remote underwater region stretching across the Indian Ocean.

Researchers describe the area as a vast "whale-fall community supercorridor," a chain of habitats created by the remains of dead whales that have accumulated on the seafloor over millions of years.

When a whale dies and sinks to the ocean floor, its carcass becomes a rich source of nutrients, supporting a unique ecosystem of worms, crustaceans, molluscs and other deep-sea creatures.

The newly discovered graveyard spans around 1,200 kilometres and lies at depths ranging from 4,200 metres to an astonishing 7,002 metres below the ocean surface. Until now, the deepest known whale-fall ecosystem had been recorded at just over 4,200 metres.

The discovery began in early 2023 when scientists aboard China's deep-sea submersible Fendouzhe identified several whale fossils and active whale falls. Over the following weeks, the team carried out 32 additional dives to map the region in greater detail.

In total, researchers documented 485 whale-fossil sites, including five active whale-fall ecosystems. One of these was found at a depth of 6,789 metres, making it the deepest active whale-fall community ever recorded.

The fossils tell a story stretching back millions of years. Dating analyses suggest some remains are around 5.3 million years old, indicating that whales have been dying and sinking in this region since at least the Early Pliocene epoch.

Many fossils belonged to deep-diving beaked whales, and scientists even identified a previously unknown extinct species, which they named Pterocetus diamantinae. The site's exceptional preservation has allowed researchers to build an important archive of whale evolution that would be impossible to find on land.

The graveyard also hosts a thriving ecosystem. Scientists recorded dozens of animal groups living on and around the whale remains, including bone-eating worms, brittle stars and several organisms that may be entirely new to science.

Researchers believe the region's unique V-shaped underwater terrain may funnel sinking whale carcasses into concentrated areas. Combined with the extreme diving habits of beaked whales, this may explain why such an extraordinary accumulation of remains formed.

Experts say the discovery offers an unprecedented window into both the history of whales and the mysterious life that flourishes in the deepest reaches of Earth's oceans.

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