World's largest deep-sea whale graveyard, 5.3 million years in the making, found in Indian Ocean

(A) A 3-meter minke whale carcass discovered during a dive at 5,610 meters. (B) An enlarged view of the yellow box in image A, showing a starfish (white arrow) and a scale worm (yellow arrow) attached to the whale's skull. (C) An enlarged view of the white box in image A, showing numerous transparent tubes of bone-eating worms. [Nature, 2026]

The world's largest known deep-sea whale graveyard, formed over 5.3 million years, has been discovered at depths of up to 7,000 meters in the Indian Ocean. Stretching 1,200 kilometers, the site holds the remains of more than 480 whales — from recently sunken carcasses to fossils millions of years old — and has functioned as a vast biological corridor linking deep-sea ecosystems.

A research team led by Dr. Peng Xiaotong of the Institute of Deep-Sea Science and Engineering at the Chinese Academy of Sciences published the findings in the 2026 issue of Nature.

At 7,002 meters down: a scene no one had ever witnessed

(D) A beaked whale carcass found during a dive at 5,609 meters. (E) An enlarged view of the white box in image D, showing three vesicomyid bivalves (white arrows) and a starfish (yellow arrow). (F) Whale bones recorded at 4,625 meters. (G) The deepest whale carcass observed, at 6,788 meters. [Nature, 2026]

The discovery was made during an expedition in February and March 2023. Using a research vessel equipped with a crewed submersible capable of diving to 11,000 meters, the team carried out 32 seafloor dives and surveyed 127 kilometers of ocean floor, confirming whale bones and carcasses at 485 sites.

Among the finds were five modern whale carcasses and 476 whale fossils distributed across the 1,200-kilometer stretch. In the most fossil-dense zones, the team calculated a concentration of 760 specimens per square kilometer.

The first bones turned up at 7,002 meters. The previous record for the deepest whale carcass ever found was 4,204 meters, in the southwestern Atlantic — making this discovery more than 2,800 meters deeper than any prior record.

A whale carcass. This image is not directly related to the article. [Getty Images Bank]

When a whale carcass sinks to the seafloor, its decomposition over decades gives rise to a unique surrounding ecosystem. In the nutrient-starved deep sea, a single whale carcass can supply enough food to sustain nearby organisms for decades — which is why scientists call the phenomenon an "oasis on the ocean floor."

This expedition confirmed the presence of a range of deep-sea specialists around the bones: bone-eating osedax worms, clams that survive on sulfur compounds seeping from the skeleton, starfish, and crustaceans.

Why did the remains accumulate here in particular?

Orange circles mark dive sites where whale fossils or carcasses were observed. The larger the circle, the greater the number of whale specimens found. [Nature, 2026]

Fewer than 70 such sites have ever been identified worldwide. The research team traced the unusual concentration of whale remains in this stretch to the zone's topography, the behavioral traits of the whales themselves, and the distinctive conditions of this body of water.

The trench formed roughly 60 million years ago when Australia and Antarctica split apart, creating a V-shaped canyon. That deeply incised canyon acts as a funnel, drawing sinking whale carcasses down to the floor.

Most of the fossils belong to beaked whales, which hunt squid in the deep ocean and regularly dive beyond 1,000 meters. When they die from exhaustion after repeated dives near their physiological limits, their bodies sink to the canyon floor.

The team also pointed to the area's unusually slow sedimentation rate as a contributing factor. Less than 0.55 centimeters of sediment accumulates on the seafloor here every one million years, meaning bones that sink are never buried.

The rostral bones of beaked whales are the densest of any living vertebrate, which also slows their decay. Over time, the bone surfaces become coated with iron and manganese oxides, further enhancing preservation and allowing the bones to remain intact for millions of years.

New whale species and undescribed deep-sea creatures found in abundance

The team dated 33 fossil specimens by comparing the ratios of specific elements preserved in the bone against the known seawater composition of different geological periods, working backward to estimate their age.

The oldest fossil was estimated to be 5.26 million years old and belonged to an already-extinct species of beaked whale. The finding indicates that whale remains have been accumulating in this zone for at least 5.3 million years.

The expedition also yielded a previously unknown extinct whale species. Named the "Diamantina beaked whale" after its discovery site, the creature resembles living beaked whales but has a distinctive skull structure in which the orbital processes flare outward like wings.

Around the five carcasses that still retained organic material, the team identified a total of 35 animal species.

Only one — a bivalve — could be identified to the species level through genetic analysis. Most of the rest are believed to be new species not yet registered in scientific literature.

One section of the site held up to 2,840 organisms per square meter. A type of starfish known as a "sea daisy" was also recorded for the first time at depths of around 5,600 meters, on whale bones.

A biological stepping-stone, unbroken for 5.3 million years

According to the prevailing hypothesis, whale bones serve a dual role on the deep seafloor: as a food source and as a stepping-stone to the next habitat. Organisms living near hydrothermal vents or cold seeps cannot travel far on their own, making such intermediate waypoints essential.

The team said the discovery supports that hypothesis. Whale bones lined up continuously across 1,200 kilometers show that this chain of stepping-stones has remained unbroken for 5.3 million years.

The team also suggested that similar mass accumulation sites likely exist in other oceans where beaked whales live — including waters off southern Africa, the Iberian Peninsula, and around the Crozet and Kerguelen Islands in the Southern Ocean.

Reference

DOI: 10.1038/s41586-026-10546-z

Peng, X., Zhou, P., Song, X. et al. A 5.3-million-year-old deep-sea whale necropolis in the Diamantina Zone. Nature (2026).