For over 60 years, scientists believed they had found some of the oldest human fossils in Japan in the Ushikawa district. But a new study has completely flipped that idea on its head. The bones, which were thought to belong to an ancient human, are actually not what they seemed.
The fossils were first unearthed in the late 1950s, and for decades, they were considered a major find. Researchers thought they had discovered the bones of a human who lived more than 20,000 years ago. But with new research methods, including advanced CT scanning, scientists have just revealed what those bones really belong to.
How the “Human” Fossils Were Misidentified
The Ushikawa fossils were originally thought to be from a human because of the shape and structure of the bones. They included a humerus (upper arm) and a femur (leg), which scientists assumed belonged to an ancient human who lived in Japan more than 20,000 years ago.
But the recent study, published inAnthropological Science, shows that these bones are, in fact, from a brown bear (Ursus arctos). The humerus was actually the radius bone from a bear’s forearm, and the femur also belonged to a bear.
This isn’t the first time a fossil was misidentified. In the 1980s, another fossil called “Akashi Man” was thought to be human, but further research revealed it wasn’t.
The Technology That Solved a Prehistoric Mystery
How did scientists figure out the bones weren’t human after all? The key came from using modern CT scans, which allowed researchers to examine the bones in more detail than ever before. According to one of the researchers, Gen Suwa, the scans revealed that the bones were clearly from a brown bear, not a human.
The CT scans showed features that are unique to bear bones, such as the shape of the humerus and femur, which helped confirm their true identity.
“From these observations and taking into account the individual variation in bear bone morphology, we were able to determine that the Ushikawa ‘human humerus’ fossil is a fragment of the shaft of a bear’s radius, and that the femoral head fossil is also bear bone,” said the authors.
What This Means for Japan’s Prehistoric Timeline
With the Ushikawa fossils now confirmed as bear bones, the oldest human fossils in mainland Japan are now believed to date back around 14,000 to 17,000 years, found in a quarry near Hamakita. This shifts the timeline of human occupation in Japan and helps paint a more accurate picture of early human life in the region. There are also human fossils found on the Ryukyu Islands, which could date back to as early as 32,000 years ago.
The Ushikawa discovery isn’t the first time bones have been misidentified. For example, another study published by theUniversity of Chicago Press Journalsreported that a bone once thought to be from a bear in Alaska was later found to belong to a Native American woman who lived around 3,000 years ago.
“Although the ‘Ushikawa man’ remains were found to be nonhuman, their historical scientific significance as a contribution to the subsequent development of paleoanthropological research remains unchanged,” as cited by the Japanese newspaperMainichi.
These mistakes highlight the challenges paleontologists face when identifying ancient remains, especially when tools and technology were limited back then.
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