Hidden Identity of the ‘Dragon’ Mummy Revealed At Last

On this year 2025’s Father’s Day weekend, the film live adaptation of How to Train Your Dragon has dazzled audiences everywhere. The movie’s cutting-edge visual effects conjures the amazing imagery and magic of dragons, which in turn, has renewed peoples’ deep fascination for these mythic creatures with fresh hot energy. The film even soared to box-office success, thus proving that our interest in dragons is as resilient as ever. Yet, beyond the silver screen lies a real-world mystery wrapped in centuries of folklore. While the movie gave us Hiccup and Toothless, our real-life world presents us with the Koryu dragon mummy hailing from Japan.

The Koryu (Rainbow Dragon) mummy has been long revered for its unforgettable features and rumored magical powers since medieval Japan. It is important to note that the dragon mummy has been cherished as an iconic treasure in one of the country’s most sacred Buddhist temples – the Todaiji Temple. Having charmed scholars with its serpentine appearance for generations and was believed to hold cosmic weather-controlling powers of summoning rain during the Muromachi Period (Japan’s medieval ages). The most exciting news of all, however, is that this ancient relic has finally been unmasked by science… and my goodness, the data results present us with an unexpected identity of the creature.

With that being said, let us now present to you the identity of the dragon mummy, shall we?

When you’re ready to find out the mummy’s identity…

just keep scrolling below.

Lo, and behold:

It turns out that the mummy’s in fact an adult female Japanese marten (Martes melampus). Cousins to weasels rather than being cousins to giant reptilian creatures of myths.

Standing at about 40 centimeters long (approx. 15.75 inches), the Koryu mummy’s enigmatic aura earned itself a legendary status. However, its transformation from myth to zoological fact was solidified through recent breakthroughs. Scientists deployed X-ray imaging and radiocarbon dating, discovering that its teeth and head bones confirmed its mammalian origins rather than reptilian or supernatural. The dating pinpointed its age as between the 11th and 12th centuries.

The intriguing history of the Koryu mummy bridges folklore with science too. The mummy’s first documented connection to dragon myths takes us to the year 1429. It was in this timeframe when the Muromachi shogun (commander-in-chiefs during medieval Japan) named Ashikaga Yoshinori would have his fateful encounter with the mummy during his visit to Todaiji Temple in Nara – one of Japan’s oldest cities.

Nara’s Todaiji Temple contains a storehouse called the Shōsōin Repository where prized religious artifacts and treasures were kept, such as the valuable Ranjatai agarwood and of course.. the enigmatic Koryu mummy. When Ashikaga Yoshinori visited the repository in 1429 to handle relics such as the Ranjatai, he would eventually encounter the Koryu mummy by chance with the assistance of the temple monks. Its dried, dragon-like appearance captivated the shogun’s first sight. After gazing into the mummy and marveling at its otherworldly looks, the shogun likened it to a mythical Koryu – rainbow or flood dragons of East Asia – thus sparking the mummy’s association with these legendary creatures in historical records.

Diaries from Todaiji Temple’s monks during that time period have recorded the shogun’s visit, and ever since then, the dragon mummy became further entwined with local folklore. That was when the citizens of Nara believed the mummy’s presence could summon rain whenever the repository was opened, as Eastern dragons were associated with both the weather and water; in contrast to the Western dragon’s fiery nature.

While skeptics might assume this marten to have simply wandered into the repository and succumbed to its death either by old age or starvation, researchers have speculated that the temple’s monks may have intentionally preserved or assembled these displays. Then, there’s more: the marten wasn’t the only ‘dragon’ mummy found in the storehouse. Fragmented parts of other so-called ‘Koryu’ mummies were also unveiled from Todaiji Temple. These parts have been revealed to be mole legs and bird bones. This additional find has led researchers to hypothesize that monks might have curated these relics to craft fantastical displays, possibly to captivate or inspire awe among the local community. However, this remains speculative and not definitively proven (as of June 2025).

To further add mystery to this whole discovery, the research team reported an uncanny alignment with the past. Listen to this: during preparations for the investigation of the Koryu mummies, heavy rain popped up out of the blue. This heavy rain disrupted the team’s plans and gave them quite a memorable experience. One could say that this was a playful nod to the Koryu dragon’s legendary status as a rain-bringer. Coincidence perhaps? Who knows.

From myth to marten, the Koryu embodies a beautiful tapestry of history, natural science, and human imagination. While its identity has now been demystified, its story continues to enchant us, reminding us of the treasures hidden at the crossroads of fact and folklore. Even though its true nature has been revealed, the Koryu remains cherished to the city of Nara and its people. For in the creative minds of mankind, the symbolism of dragons still endures and captivates our imaginations in its supernatural form. Look no further than the movie How to Train Your Dragon, which continues to win the box office as its story rekindles humanity’s timeless dream of dragons.

Header Image: Zoomed in photograph of the dragon mummy. From the No. 47 Bulletin of Office of the Shōsōin Treasure House.

References:

1.  Imai, Kunihiko. “Experts Identify the Species of Shosoin’s Famed ‘Dragon’ Mummy.” Asahi Shimbun, 24 Apr. 2025, www.asahi.com/ajw/articles/15723856.

2. Odeen-Isbister, Sara. “Mystery of 600-Year-Old Mummified ‘Dragon’ Solved.” MSN News, www.msn.com/en-sg/news/other/mystery-of-600-year-old-mummified-dragon-solved/ar-AA1GFoH3.

3. Margolis, Andrea. “Experts Solve Mystery of Ancient ‘Mummified Dragon’ Discovered by Japanese Shogun.” Fox News, 27 May 2025, www.foxnews.com/travel/experts-solve-mystery-ancient-mummified-dragon-discovered-japanese-shogun.

Written by Zeffs Amman

Zeffs Amman, our resident writer and globetrotter at AllThatHistory! Having grown up in five different cultural landscapes and lived in multiple countries, Zeffs brings forth a wide collection of intercontinental knowledge to activate readers' minds. His treasure trove of experiences spans roles as a historian, herbalist, perfumer, critic, entrepreneur and even mythographer to better grasp the supernatural world. Zeff's journey across the planet has equipped him with the ability to bridge gaps between different people, ideas, generations, and religions. His hands-on approach to learning through in-depth insights offers readers the tools to better perceive the complex, interconnected world we live in. At AllThatHistory, Zeffs brings the world to you — inspiring a deeper understanding of our shared planet.