Sep 27, 2014 I Brent Swancer

The Thunder Beasts of Japan

Since the dawn of time, humans have looked to the skies with a sense of wonder, awe, and fascination. The wind, the sky, clouds, thunder and lightning, these are things have captured the imagination of humankind and held an undeniable mystical quality for us since time unremembered. Since long before the age of reason and science, people have gazed at the heavens and sought to explain the various phenomena of the vast skies above, to find some way to grasp how these wonders fit into the universe that they know.

In Japan, thunder and lightning were the elements of the Raijū, or literally “thunder beast,” the mighty servants of the Shinto god of thunder. These creatures were most often described as looking something like a badger, weasel, cat, or fox, although they were sometimes said to look like a wolf or monkey as well. Some accounts speak of the creatures having wings, or having multiple tails. They are quite often dramatically depicted as being wreathed in crackling tendrils of lightning, and their voices were said to boom like thunder. Raijū were said to descend to the earth upon lightning bolts, to ride atop lighting, or to travel about in hovering balls of lightning. Typically the Raijū were said to be fairly docile in nature, but during storms would become extremely agitated and aggressive, ignite with lightning, and frantically dash about leaping from tree to tree, tearing up the bark in the process with their formidable claws. In old Japan it was said that trees scored by lighting had been the work of Raijū claws, and that scorched tree trunks were the result of their wrath.

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With all of this fierce and dramatic imagery of flickering lightning and cracking thunder surrounding the Raijū, it is perhaps no wonder that the people of Japan have long feared and respected these otherworldly creatures. Additionally, although they may seem at first to be a totally mythical construct, these beasts were once considered to be quite real to the people of Japan. Most locals in rural areas were well aware of which woodlands were inhabited by Raijū and were careful to stay away during storms. In fact, areas said to be the lairs of the Raijū were for the most part avoided altogether, as they invoked a potent fear in most people.

The fearsome reputation of Raijū was not helped by the fact that these thunder beasts were thought to be fond of swooping down from trees to bite and slash indiscriminately at passersby. It was said that one of the favorite targets of Raijū was the navel, which prompted many to protect their stomach with armor or heavy cloth wound about the midsection, or lie face down during stormy weather. Yet for all of the power and menace they projected, Raijū were thought to be curiously unable to pass through mosquito nets, and also to abhor the smell of burning incense. During storms it was not uncommon for villagers in rural areas to burn large amounts of incense or to erect nets in an effort to deter the beasts.

Japan has a long history of stories concerning these strange entities falling from the sky, and a few reports even tell of them being killed and eaten by farmers. Other stories tell of angry farmers attacking and killing the creatures when they infested forests and began to rage out of control. There are additionally many accounts of these fallen Raijū actually being captured alive. One such account concerns a Raijū that was captured in the 18th century on Mt. Asama, Shimane prefecture. This specimen was then kept in an iron net and put on display for all to see. Most onlookers described the animal as looking like something between a fox and a weasel, and possessing sharp, curved claws. The creature refused to eat or drink during its captivity, and would become extremely agitated before the evening rain. During stormy weather, its hair would stand on end and it would emit a high pitched, shrieking noise that instilled fear and panic in anyone within earshot.

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A samurai fighting with a Raijū

Another such creature was captured in the fiefdom of Lord Nagai, in the Iwatsuki ward of Saitama prefecture. The Raijū was allegedly caught while tearing through a garden and damaging vegetables in the aftermath of a storm. Upon its capture, the creature was kept for a time in a cage before it died from refusing to eat or drink. The animal was reported to have the unusual appearance of a puppy with the claws of a bear. The feet were described as having many knuckles, and the pelt was thin except for thicker fur beneath the legs.

One Raijū allegedly fell into a well in Izumo province, where it became hopelessly entangled in ropes and was captured alive. The creature was subsequently exhibited within a cage of brass in the court of the temple of Tenjin, in Matsue city. The animal was said to resemble a badger. When the weather was clear, the Raijū was quite docile and quiet, sleeping peacefully in its cage most of the time. On occasion, it was said to even perform tricks and antics for curious onlookers. However, during storms it would transform into a ferocious, hissing beast, barely contained by its cage and with eyes that were said to flicker and flash ominously as if filled with lightning.

A farmer captured yet another Raijū in 1766, when one fell from the sky in Oyama in the Sagami province. The farmer showed the animal for money on the Riyo-goku bridge. It was described as black in color, a little larger than a cat, and having the appearance of a weasel. Each of the creature’s paws was adorned with five prominent, vicious looking claws. Similarly to the other captured Raijū described so far, this specimen was also tame and lethargic during calm weather, yet savage during storms, during which it would furiously rattle and claw at its cage, as well as snap at anyone who got to close to it. It also refused any food given to it.

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A Raijū in aggressive mode

Various sideshows would often exhibit what were claimed to be Raijū as well. Such creatures were almost always described as having been captured after storms, and typically had the appearance of something weasel-like in nature with prominent, sharp claws. Sideshow owners would sometimes dress them up in traditional clothing, and make a big event out of stormy days, when predictably the beasts would become snarling, whirling terrors, much to the delight of paying customers.

In addition to live Raijū, there are many alleged mummies of these creatures kept in locations around Japan. One such mummy is kept at Yuzanji temple in Iwate prefecture. The mummy looks very much like a cat, only with longer legs and no discernible eye sockets. It was allegedly received in the 1960s as a donation from a parishioner, although the exact origin of the mummy is not known. Another similar looking Raijū mummy is kept at Saishoji temple in Niigata prefecture. The sacred nature of these artifacts makes any DNA testing unlikely, however there is a very good possibility they are examples of elaborate gaffes, or creative taxidermy.

The accounts of creatures riding balls of lightning or crashing to the ground upon lightning bolts may understandably make many skeptical of the existence of a creature like the Raijū. With such fantastical elements, it may appear as though these are surely beasts from the depths of human imagination rather than from the sky. At the very least it seems obvious that accounts of these creatures have been heavily embellished and imbued with folkloric elements. However, is it possible that somewhere at the heart of this folklore, there might be a zoological explanation for the Raijū?

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One depiction of a Raijū

Certainly the ancient Japanese, like those of many cultures throughout the world, would have looked upon natural phenomena such as storms with a sense of curiosity and awe. Lacking an understanding of science, they may have tried to explain these things with supernatural tales of divine thunder beasts sent down from the skies. Many known animals in Japan have been linked in folklore with a wide range of natural phenomena. Perhaps with the Raijū we have something that similarly started as a real animal, that subsequently became associated with storms and lightning through an attempt to come to grips with these forces, and thus became entrenched in mythological lore. It might have started with something as simple as someone seeing a tree struck by lightning and the animals in question running for cover, which might have given the impression that these creatures had fallen down in a bolt from above. Tales of the Raijū flying within spheres of lightning may have been an attempt to explain ball lightning in the context of an animal they knew about. Could the Raijū have been a real animal seen though the lens of superstition concerning the power and mystery of nature?

Indeed, if one strips away the more outlandish elements such as riding lightning or flying in balls of plasma, we are left with something that seems consistent with a flesh and blood animal. But what kind? The physical description and disposition of the Raijū seems to fit in very well with something perhaps from the Mustelidae family of mammals, which encompasses a wide range of carnivores, including badgers, weasels, wolverines, and otters, a few species of which are native to Japan. The Raijū accounts tell of something that seems very much like a mustelid in appearance, often describing them as badger or weasel-like. Mustelids are also known for their sharp teeth and claws, much like the Raijū. On wolverines or a burrowing mustelid such as the badger, the claws are especially quite pronounced, just as in Raijū reports, and such claws would also make sense for a tree dwelling animal like the Raijū for use in climbing. The general fierce disposition and aggressive temperament of some mustelids also fits in well with what is reported with Raijū.

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The Japanese marten, a type of mustelid found in Japan

Or is the Raijū based on a type of primate? The only species of primate found naturally in Japan is the Japanese macaque (Macaca fuscata) which are found throughout the archipelago, except the northern island of Hokkaido. These macaques are semi arboreal, spending about equal amounts of time on the ground and in trees. They are also known to leap quite well and could be responsible for the shrieking sounds sometimes associated with Raijū, which were also occasionally described as looking like a monkey. It’s possible that macaques, or even an unknown species of primate could have been the basis of Raijū tales, however, the majority of descriptions give a weasel or badger like appearance that seems more consistent with a mustelid.

Known animal behavior seems to parallel some of that displayed in Raijū lore. Tales of Raijū leaping from tree to tree match up well with the sort of behavior exhibited by an arboreal predator such as the marten and sable, or a creature like the macaque. It is also quite possible that the storms with which Raijū are associated could further agitate some animals and even cause them to panic. Many animals are able to sense changes in barometric pressure, ozone concentrations, and humidity before a storm, and can demonstrate a wide range of behaviors in response, including increased uneasiness or agitation. There is also the additional element of booming thunder and lightning, which can cause a fear response in some animals, as anyone who has owned dogs can surely attest to. It seems plausible that storm conditions such as these could on occasion cause an arboreal animal to panic, dash about, leap from tree to tree, or otherwise show signs of the increased state of agitation or even the aggression present in Raijū accounts during foul weather.

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Japanese macaque

The same fearful reactions may explain the keyed up behavior of the alleged captured Raijū, during bouts of bad weather. An animal captive in a cage or any enclosed, restricted space could feasibly become quite distressed under storm conditions. For instance, some of the fear responses for domestic animals can include hiding, uneasiness, trembling or shaking, a strong flight response or drive to escape, or outright panic. It's not too hard to imagine that the cases of captive Raijū displaying this sort of behavior, such as agitation, hair standing on end, and clawing at their cage, could have had something to do with a similar fear response due to storms. For an animal already strongly associated with storms, people would naturally assume it was due to the animals somehow being powered up by the thunder and lightning.

The refusal to eat so often mentioned with captive Raijū is also not unheard of with wild animals forced into captivity. This is a challenge often faced with some species that are hard to keep, and indeed some can even die from this, much like what was reported with captured Raijū. Even the flickering eyes reported in the case of the Raijū captured in the well in Izumo could be explained in terms of a flesh and blood animal, as the perceived flashing might have been caused by eye shine brought upon by the lightning or some other light source.

In light of this information, it seems at least worth considering that the Raijū legend could possibly have its basis in some type of arboreal mustelid or a creature very much like one, exhibiting known and documented animal behaviors. Perhaps these very real animals at some point became entwined with the Japanese perceptions of storms and lightning, and thus were inextricably linked with lore concerning these weather phenomena.

If we are indeed dealing with a real animal, were these creatures a currently known extant species, an extinct species, or something undocumented? It is difficult to say as there is practically no representation of Raijū in modern reports. This may mean that modern understanding of animals and storms has caused a rift between what is known as real and what is known as pure folklore. The increasing understanding of how our world works can cause superstition and folklore to become regulated from something once seen as very literally real, to the world of myth. With the Raijū, what was once thought of as a servant of the god of thunder may now be recognized as a known, mundane animal, and so the folklore perhaps simply did not carry over into the modern day as reality. In essence, a mustelid or macaque is now known to be just that, and so reports of Raijū might have died along with widespread belief in such magical beliefs as servants of the thunder god mounted atop lighting bolts.


In that sense, perhaps now when someone sees for instance a Japanese marten, they are more likely to see that animal for what it is, without the accompanying folklore and magical powers surrounding it. A good example of this shifting status is the Japanese fox, which was once seen as a very mystical animal with many supernatural powers. In more ancient times, foxes would be described as doing all manner of magical things, and seeing one was hardly a mundane occurrence. Yet in modern times, a fox is seen as just a fox, and thus there are no longer reports of the more folkloric version of the fox. Many of the known animals once seen as magical are now perceived as more mundane. Has some similar transformation happened with the animal or animals at the heart of the stories of Raijū?

Lack of modern day sightings could also mean that whatever the Raijū was is now extinct, and thus we may never know what species it belonged to. Or perhaps there is even the possibility that this is a rare, undocumented species that may be still lurking out there somewhere right now.

So what are we left with? If the Raijū was ever based on a real animal, its origins have been lost to the mists of time and we are forced to speculate. Did the Raijū originate from a living, breathing creature, or was it the fabrication of a populace trying to make sense of the natural world? Is there an existing creature, known or unknown, that can account for the folklore? What lies buried at the heart of this fantastic creature of lightning and storms? The answer may forever remain a mystery.

Brent Swancer

Brent Swancer is an author and crypto expert living in Japan. Biology, nature, and cryptozoology still remain Brent Swancer’s first intellectual loves. He's written articles for MU and Daily Grail and has been a guest on Coast to Coast AM and Binnal of America.

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