Researchers have found the oldest, deepest, and most extensive whale graveyard ever documented in the south-eastern Indian Ocean. The discovery reveals fossils dating back more than 5 million years, offering an extraordinary window into marine history and deep-sea ecosystems.
The site, located in the Diamantina fracture zone, differs dramatically from previously known whale graveyards. While most whale falls have been found at depths less than 2.5 miles, this necropolis extends beyond 4.3 miles deep and stretches hundreds of miles across the ocean floor. A team of researchers from China, Italy, and New Zealand used submersibles to explore the area, conducting 32 dives that uncovered 485 whale-fossil sites and five modern whale carcasses still decomposing.
The Diamantina fracture zone formed between 50 and 60 million years ago as the Australian and Antarctic continents separated. Within this underwater trench system, the researchers discovered whale remains aligned along a northwest-southeast axis spanning about 750 miles, potentially forming what they call a "whale-fall community supercorridor."
Among the finds was a five-meter-long skeleton of an Antarctic minke whale, the largest specimen discovered. The team also identified remains of extinct species, including a fossilized skull from a beaked whale species called Pterocetus benguelae, dated to 5.3 million years ago, and bones from a previously unknown beaked whale species they named Pterocetus diamantinae.
What makes this discovery particularly significant is the thriving ecosystem surrounding the decomposing remains. The whale carcasses support diverse life forms including crustaceans, molluscs, bone-eating worms, and brittle stars. Many of these species may be new to science, according to researchers.
Dr. Giovanni Bianucci from the University of Pisa noted that the discovery demonstrates how life adapts and evolves in extreme environments lacking light and characterized by extreme pressure. He emphasized that the findings reveal species and ecosystems still unknown to science, highlighting how much remains to be discovered about ocean biodiversity.
The concentration of nearly 800 skeletons per square kilometer puzzles researchers. The site contains an unusual mix of whale species, including both shallow-diving filter feeders like minke whales and deep-diving hunters such as beaked whales. Scientists suggest the location may have served as a migration route for filter-feeding whales while also providing ideal hunting grounds for deep-diving species pursuing squid, though these hunters may have pushed themselves dangerously close to their physiological limits in these extreme depths.
The study was published in the journal Nature and represents what colleagues describe as a rare and exciting discovery, opening new avenues for understanding whale evolution and ocean conditions across millions of years.