Haunting 'mermaid' mummy discovered in Japan is even weirder than scientists expected

A shot of the "mermaid" when it went on display for journalists in February 2022. (Image credit: The Asahi Shimbun)

A centuries-old mummified "mermaid" that scientists recently revealed to be a gruesome doll of animal parts is even weirder than previously thought, new findings show.

In 2022, researchers discovered the mermaid, which is around 12 inches (30.5 centimeters) long, lying inside a sealed wooden box within a Japanese temple, located in Okayama Prefecture. At the time, researchers thought it was made from the torso and head of a monkey sewed onto a decapitated fish's body

The haunting hybrid, which resembles a Ningyo from Japanese mythology — a fish-like creature with a human head that is fabled to help cure disease and increase longevity — had previously been displayed in a glass case at the temple for people to worship, before being stored away more than 40 years ago. A letter inside the mummy's box claims that the specimen was caught by a fisher sometime between 1736 and 1741, but it was likely created decades after that as a hoax to sell to affluent people wanting to improve their health or live longer lives. 

Researchers from the Kurashiki University of Science and the Arts (KUSA) in Japan took possession of the mermaid in early February 2022 (with permission from the temple's priests) and began studying the eerie artifact using a range of techniques including X-ray and CT (computerized tomography) scanning, radiocarbon dating, electron microscopy and DNA analysis. 

Related: Haunting images of 'zombie' shark and other decaying aquarium animals revealed in eerie footage 

A CT scan of the mermaid used in the new research. (Image credit: KUSA)

On Feb. 7, the team finally released its findings in a KUSA statement (translated from Japanese). And what they found out about the mermaid was even more bizarre than expected.

The results showed that the mermaid's torso did not belong to a monkey but instead was made predominantly from cloth, paper and cotton that was held together by metal pins running from the neck to lower back. It had also been painted with a paste made from a mix of sand and charcoal. 

However, the torso was covered in components stripped from other animals. Mammal hair and fish skin, likely from a pufferfish, covered parts of the arms, shoulders, neck and cheeks. The mermaid's jaw and teeth were also likely taken from a predatory fish, and its claws were made from keratin, meaning they likely came from a real but unidentifiable animal.

A digital reconstruction of the mermaid showing different layers of the "body." (Image credit: KUSA)

The lower half of the mermaid did come from a fish, likely a species of croaker — a ray-finned fish that makes a croaking sound with its swim bladder, which helps it control its buoyancy.

The researchers were not able to identify any complete DNA from the mermaid, but radiocarbon dating of the scales indicated they could date back as far as the early 1800s.

The new analysis suggests that the mermaid was most likely created to trick people into believing that Ningyos and their supposed healing abilities were real, researchers wrote. However, it also shows that the tricksters behind the creation also put much more effort into stitching together the counterfeit creature than expected.

There are 14 other "mermaids" that have been found in Japan, and the team now hopes to analyze others for comparison.

Harry Baker
Senior Staff Writer

Harry is a U.K.-based senior staff writer at Live Science. He studied marine biology at the University of Exeter before training to become a journalist. He covers a wide range of topics including space exploration, planetary science, space weather, climate change, animal behavior, evolution and paleontology. His feature on the upcoming solar maximum was shortlisted in the "top scoop" category at the National Council for the Training of Journalists (NCTJ) Awards for Excellence in 2023.