 "The 20,000-year-old bone, thought to belong to ancient human(s), turned out to be of another animal altogether. AI-generated image via DALL-E")
The 20,000-year-old fossilised remains of what was thought to be one of Japan’s oldest humans, known as “Ushikawa Man,” are actually the bones of an ancient bear, new research has revealed.
The fossils, unearthed in the late 1950s in the Ushikawa district of Toyohashi, about 140 miles southwest of Tokyo, have long been considered among Japan’s most significant prehistoric discoveries. However, doubts about their human origin surfaced in the 1980s and have now been definitively resolved.
A study published in the journal Anthropological Science confirmed that the fossils belong to a brown bear (Ursus arctos), LiveScience reported.
Historical misidentification
The Ushikawa fossils were initially identified as parts of a human humerus (upper arm bone) and femur (leg bone), believed to be over 20,000 years old.
But Suwa’s team used computed tomography (CT) scans and visual analysis to conclude that the humerus was actually a bear’s radius (forearm bone), and the femur was also from a bear.
Suwa noted that bear bones from this period are rare in Japan, and palaeontologists in the 1950s had limited knowledge of their characteristics. Despite the misidentification, the researchers at the time made “detailed and very accurate” descriptions and collected an extensive fossil record.
Shifting narratives
The reassessment of the Ushikawa fossils follows earlier scrutiny of another purportedly ancient human find in Japan. A fossil fragment known as “Akashi Man,” thought to be more than 780,000 years old, was lost during an Allied air raid on Tokyo in World War II.
In the 1980s, an analysis of a plaster cast suggested it was likely a modern human bone that had been misplaced in a different archaeological layer.
This earlier misstep spurred greater attention on the Ushikawa fossils, ultimately leading to their reclassification as bear bones.
Oldest human fossils in mainland Japan
The discovery means that the oldest confirmed human fossils on Japan’s mainland now come from a limestone quarry near Hamakita, about 25 miles east of Ushikawa.
These remains include fragments of a leg bone, arm bone, collarbone, and skull, attributed to two individuals who lived approximately 14,000 and 17,000 years ago.