Scientists Discover a 5-Million-Year-Old Whale Graveyard Deep Beneath the Indian Ocean

A deep ocean whale graveyard is revealing new clues about whale evolution and the ecosystems that form around their remains.

When a whale dies, its body can become the beginning of an entire deep ocean ecosystem. For a time, the carcass may drift at the surface, drawing sharks and other predators. Eventually, after weathering and losing buoyancy, it can sink through the water column and come to rest on the seafloor, where scavengers and other deep-sea organisms feed on the remains.

These events, known as “whale falls,” are difficult to study because they are rare to find and often occur far beyond easy reach. The scientific record is still scattered and incomplete. Now, a team led by Xiaotong Peng from the Chinese Academy of Sciences has identified a vast ancient whale graveyard in the Diamantina Zone of the southeastern Indian Ocean.

The site, described in a new Nature paper, is more than five million years old and ranks among the deepest known whale fall ecosystems ever documented.

A whale-sized find in the middle of the ocean

The discovery came during a special dive mission in February 2023, when scientists used the submersible Fendouzhe to explore the seafloor. There, they found extensive whale skeletons and fossil remains partly buried in sediment, revealing a deep ocean site where whale carcasses had once supported life long after death.

Following the initial discovery, the team made 32 more dives to the seafloor over the next month, mapping the extent of the necropolis.

It stretched roughly 1,200 kilometers along the seafloor at depths of between 4,200 and 7,000 meters. It contained 476 whale fossils as well as five active whale falls.

These active whale falls were teeming with many strange-looking creatures, including jellyfish, brittle stars and bone-boring worms – many of which may be new to science, according to the researchers.

From the 43 fossils the team recovered, they identified five beaked-whale species, including the Andrews’ beaked whale (Mesoplodon bowdoini) and the strap-toothed whale (Mesoplodon layardii) which are known to inhabit the region, and one species of baleen whale – the sei whale (Balaenoptera borealis).

The largest find was a dead Antarctic minke whale, five meters in length, which the team identified from its distinct ear bone shape, as well as genetic analysis. The team also identified a new whale species – Pterocetus diamantinae – which is now extinct.

Isotopic dating, where scientists use the decay of radioactive isotopes, revealed that the oldest fossils from the site are about 5.3 million years old.

The high concentration of whale remains in the region raises the question of how exactly this graveyard was formed. The authors suggest the reason probably has to do with the V-shaped topography of the Diamantina Zone, which funnels carcasses onto the seafloor, plus the fact that many deep-diving beaked whale species are known to inhabit this part of the ocean.

A reminder of how little we know

This work deepens our understanding of whale falls and the incredible ecosystems they support. It also deepens our understanding of beaked whales – usually offshore species which routinely dive up to 1 kilometer and hold their breath for more than an hour.

The finding of five million-year-old fossils provides an evolutionary window into the history of beaked whales from the Pliocene epoch to the present day.

This research is also a humbling reminder of how little we know of the deep sea—and how when we look for something, we may just find it, and so much more.

Reference: “A 5.3-million-year-old deep-sea whale necropolis in the Diamantina Zone” by Xiaotong Peng, Peng Zhou, Xikun Song, Giovanni Bianucci, Mengran Du, Alberto Collareta, Zhaoming Gao, Tongtong Xie, Mingyao Teng, Daniel Leduc, Sadie Mills, Kaiwen Ta, Jiwei Li, Taoshu Wei, Shamik Dasgupta, Hao Liu, Yuan He, Wenjing Xu, Shuangquan Liu and Hanyu Zhang, 10 June 2026, Nature.
DOI: 10.1038/s41586-026-10546-z

Adapted from an article originally published in The Conversation.

Never miss a breakthrough: Join the SciTechDaily newsletter.
Follow us on Google and Google News.