Scientists have uncovered one of the largest known animal graveyards on Earth, a massive “whale necropolis” on the deep ocean floor of the southeastern Indian Ocean. Located in the remote Diamantina Zone, this site contains evidence of whale carcasses accumulating for at least 5.3 million years.
Using the crewed deep-sea submersible Fendouzhe, researchers conducted 32 dives in 2023 along a 1,200-kilometer stretch of seafloor at depths ranging from 4,616 to 7,001 meters. They documented 476 fossil whale-fall sites and five active modern whale carcasses. Based on observed densities reaching up to 760 individuals per square kilometer, the team estimates the entire zone may hold more than 10 million whale skeletons.
Whale falls create rich oases in the nutrient-poor deep sea. A single carcass can support specialized communities, including bone-eating worms (Osedax), brittle stars, anemones, and microbes, for decades. The Diamantina Zone’s V-shaped topography, low sedimentation rates, and protective mineral crusts have preserved both modern and ancient remains exceptionally well, including fossils from living beaked whale species and extinct taxa such as the newly described Pterocetus diamantinae.
This extraordinary concentration likely results from the region serving as a key feeding ground for deep-diving beaked whales, combined with seafloor features that funnel sinking carcasses into the same areas. The discovery provides a unique window into cetacean evolution and highlights how whale falls have sustained complex deep-sea ecosystems over millions of years. It also represents a significant, previously unquantified carbon sink on the seafloor.
The deepest active whale-fall ecosystem ever recorded was found here at nearly 6.8 km depth, setting a new benchmark for such communities.
[Peng, X. et al. (2026). A 5.3-million-year-old deep-sea whale necropolis in the Diamantina Zone. Nature. DOI: 10.1038/s41586-026-10546-z]