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The Mysterious Giant Worms of Japan

In the world of mystery beasts, we see strange creatures in all forms reported from the land, seas, and sky, but one type less common is that of those that lurk below our feet. Down in the dark recesses of the land beneath us there are reports from all over the world of strange things squirming through the earth, and one type of such creatures is giant earthworms, which have been reported from many areas of our planet. Among the places from which such bizarre accounts originate is the far east, and there have long been tales of enormous earthworms surfacing from time to time in various areas of Japan.

One of the hotspots for such cases is Hyogo prefecture, on Honshu Island, which has many historical accounts of worms in excess of 1.5 meters to 2 meters (5 -6.5 feet) long and sometimes even more. One such account dates from the year 1712, in what was then known as Tamba province (now part of Hyogo prefecture). The account describes a huge landslide that occurred in a village, after which 2 giant earthworms were found in the debris. One of these worms measured 1.5 meters (5 feet) in length, while the other was larger still, at 3 meters (10 feet) long. Another landslide that occurred in the same general vicinity allegedly unearthed a 4.5 meter (15 feet) long worm. A more modern report from Mikata-gun, which is located in the mountains of Hyogo prefecture, dates from 1996 when a farmer uncovered an earthworm 1 meter (3.3 feet) long and 2cm (0.8 inches) thick while planting a tree on his rural property. It was the first time the surprised farmer had ever encountered such a large worm in all his years in the area.

Mountains in Hyogo prefecture

Giant worms have been reported from other parts of Japan as well. In Okayama prefecture, one woman claimed to have seen a worm 3 meters (10 feet) long in a field that was being tilled. The worm had apparently been disturbed by the farming activity and was rather active. Another farmer in the same prefecture brought up a still thrashing piece of a worm that had been hacked off during farm work. The piece is estimated to have come from a worm 3.5 to 4 meters (11.5 to 13 feet) long. The rest of the worm could not be located. Slightly smaller worms measuring between 60cm (2 feet) to 1 meter (3.3 feet) have been occasionally reported from Okayama prefecture, Shikoku Island, the Izu peninsula, the Kii peninsula, and Nara prefecture as well.

Perhaps the strangest report comes from Fukuoka prefecture, on the southern island of Kyushu. In 1997, a Mr. Ou Sato and his friend spotted something odd near the side of a river that they at first took to be a hock of ham someone had discarded. Thinking this to be a bit odd, the two approached to get a better look at it. On closer inspection, they found the mysterious object to be a tubular piece of flesh, 30 cm (1 foot) long and 20 cm (8 inches) in diameter, with thin, glistening wet skin. There were clear grooves encircling it like those of an earthworm’s segments, and the color was described as brown, like “a bursting sausage.” There was no evidence of the object possessing bones of any kind. Both ends of the curious piece were ragged and torn, leading the two men to estimate that it was obviously a piece from the carcass of a much larger animal. The witnesses’ impression was that it originated from a gigantic earthworm, which they estimated the full length as being perhaps 10 meters (33 feet) or more. Unfortunately, due to the slimy, smelly, and slightly decomposing nature of the find, they left it where it lay.

Equally enormous and bizarre was an alleged living giant worm of truly epic proportions spotted by farmers in the 1970s, also in Kyushu. The initial witness claimed that as he had been out working his field he noticed what he at first thought to be a drum can of some sort embedded within the earth, yet as he approached he noticed that whatever it was was moving. The startled farmer called to a nearby companion and the two watched as the soil churned and shuddered and it became clear that there was a length of what looked like a “snake” protruding from underground. The approximately 1 meter long portion that was visible above ground was described as being as thick as a telephone pole and a dark, mottled brown in color, and was clearly just a part of a much larger organism. As they watched on in awe, the mysterious creature slowly sank back into the earth and it is not clear what happened after that. If this was truly a small section of a larger worm, then it would have been truly enormous.

More recent is an account from just outside of Sendai that occurred shortly after the Tōhoku earthquake on March 11, 2011. In this case the witness claimed to have been walking across a field on his way to inspect earthquake damage to some nearby houses when he spotted what he at first took to be a number of snakes on the move. As he trudged towards the field to investigate it was discovered that rather than snakes there were at least 10 worms squirming about in the field that were reported to be around 2 meters (6.5 feet) long. The witness would speculate that the creatures had perhaps been upset by the earthquake.

How feasible is it that worms of these sizes could be living in Japan? The longest known species of worm in Japan is the Seibold earthworm (Pheretima sieboldi), which reaches typical lengths of around 25 ~ 28 cm (9.8 ~ 11 inches), although specimens of around 40cm (about 16 inches) long or over have also reportedly been found on occasion. Some areas in Nara prefecture, as well as the southern Ryukyu islands have reliably documented worms from 40 to 50 cm (16 ~ 19.6 inches) long. These are big worms to be sure, but are there even more massive worms lurking in the earth in Japan that could account for the mystery reports? Although the lengths we are talking about here may seem to be firmly in the realm of myth and fantasy, the dimensions are actually comparable to a few known species of worm in nature that do reach truly enormous proportions, with the various species of giant worm having a wide distribution, and found in far flung places all over the world.

Perhaps the largest overall known species is the giant Gippsland earthworm (Megascolides australis), which is found only in the Bass River valley of South Gippsland in Victoria, Australia. These huge worms regularly reach sizes of 3 meters (10 feet), and the longest specimen on record was measured at 4 meters (14 feet) long. These rare earthworms are so large that it is possible to hear the gurgling sound of their movement through the earth when they are disturbed. In neighboring New Zealand, there is another large worm known as the North Auckland worm (Spencerilla gigantean), which reaches a length of 1.4 meters (4.5 feet). These worms have the added surprising, some might even say fairly creepy, feature of glowing in the dark. By some accounts, the light the worms emit is said to be bright enough to read by.

Giant Gippsland earthworm

The United States has its own giant worm as well. The Palouse earthworm (Driloleirus americanus) of the northwest can reach lengths of up to 1 meter (around 1.3 feet) long, perhaps even more. These worms have a historic range throughout the Palouse Prairie, which stretches out over southeastern Washington state and northern Idaho, and is sometimes even considered to encompass parts of Oregon and northwestern Montana as well. The Palouse earthworm is a striking white in color, and is said to rather unsettlingly be able to spit defensively at those that provoke it. These large worms were thought to be extinct in the late 1980s, however, in the spring of 2005 a University of Idaho graduate student located a specimen by accident during a dig. Several other specimens or parts of specimens have been reported since.

Europe also has its own giant worms. The Black Forest region of Germany is home to a 2 foot long worm known as the Giant Badish earthworm (Lumbricus badensis). Sardinia, Corsica, Italy, Sicily, and southern France are home to a species of the earthworm family Hormogaster that can get as long as 75cm (2.5 feet). Another of the largest known species is the South African giant worm (Microchaetus rappi). These worms normally grow to around 1.8 meters (6 feet) in length, but there is evidence that they can get much larger. In 1967, a South African worm was found by the side of a road in William’s Town that measured an incredible 6.7 meters (22 feet) long. This specimen remains the longest earthworm ever confirmed. Is something like this perhaps living in Japan?

The sizes given in most Japanese giant worm reports are at least within the realm of possibility considering the enormous known species of giant earthworms found in other parts of the world. There is no real reason in particular to dismiss the possibility of earthworms corresponding to these sizes or even larger in Japan, although something as big as some of the reports suggest would be unlike anything seen before. Furthermore, the very nature of the animals could help keep them hidden from human view, which could account for their elusiveness and the rarity of reports. Depending on the species, some earthworms can burrow quite deeply underground, and may rarely if ever come to the surface. Burrow systems as deep as 6 meters or more are not uncommon for some species. This would help to explain how a creature this large could go for some time with little contact with humans, thus remaining unverified. It is interesting to note that several of the Japanese giant earthworm cases were reported in conjunction to some sort of disturbance of the ground, such as a landslide or digging up of the earth. This detail seems consistent with what we could expect of a rarely seen type of earthworm lurking underground in its burrow most of the time.

The Fukuoka giant worm carcass account and the 1970s report of a worm as big around as a telephone pole are a bit more difficult to explain. The estimated length, while far beyond that of any known species of worm, is perhaps plausible for some extremely large unknown species, however the enormous diameters are another matter. Length is not necessarily a huge burden for an earthworm, but body thickness is. These are burrowing organisms that rely on being able to move as easily as possible through the soil. There are no unnecessary appendages or protuberances on earthworms, and their bodies are geared towards burrowing with as little encumbrance and as much efficiency as possible.

For this reason, you will find that even the largest known earthworms are not particularly thick in relation to their often considerable body length. For instance, the giant Australian Gippsland earthworm for all of its size is still only 2cm (0.8 inches) in diameter at its thickest point when stretched out. Likewise, the giant Palouse earthworm of the United States is typically only a half an inch in diameter. Even in the case of the longest known specimen of earthworm ever recorded, the 22 foot long South African worm mentioned earlier, the diameter was still only around 2 cm when fully extended. If a worm was any thicker than this, it would find it increasingly more difficult and less energy efficient to burrow through the ground.

In earthworms, the overwhelming message we get so far concerning their adaptations to a burrowing lifestyle is that length can be extended to an unknown degree, but thickness is apparently somewhat limited. So what are we to make of an estimate of a 20 cm (8 inch) diameter in the Fukuoka giant worm account or something akin to a telephone pole in the other Kyushu report? It just does not seem particularly likely that a burrowing worm would get quite that thick, considering what we see in earthworms that we know of. If the carcass and exposed portions of these worms were indeed part of a larger creature and consistent with the ratio of length to diameter found in known worms, it would have to have been a colossal beast of truly prodigious proportions indeed.

Perhaps it is worth considering that what was seen in these cases were not worms at all. The site where the Fukuoka remains were found was near a river, close to the water, which leads one to speculate whether some sort of aquatic creature could be the culprit. While there are aquatic freshwater worms, they are typically quite small and nowhere near the sizes being reported here. It has been speculated that an eel or even a part of a dead Japanese giant salamander could have been the culprit, but it is hard to reconcile those explanations with the descriptions given, since it is difficult to imagine what kind of creature would leave a tubular piece with no bones, as well as clear signs of worm anatomy such as the grooves or segments mentioned. Could we be dealing with some type of unknown aquatic invertebrate, perhaps one that made its way up the river from the sea? This may explain the lack of other reports of such thick worms, as well as the death of the animal in question.

Some in Japan have speculated that the Fukuoka carcass could have been part of a caecilian, a type of burrowing, snake-like amphibian. In his book In Search of Prehistoric Animals, the cryptozoologist Karl Shuker proposed just such a theory when investigating the Minhocão, a giant worm-like cryptid from South America said to measure a staggering 20 to 50 meters (65- 165 feet) in length. Shuker proposed that this creature could have been some type of enormous caecilian, which are amphibians with limbless, segmented bodies very reminiscent of the appearance of earthworms. Shuker reasoned that since these creatures are so similar looking and burrow in a manner similar to earthworms, then perhaps an extremely large, undocumented species of caecilian could be behind the reports of the Minhocão. Could the giant worm carcass found in Fukuoka also have been some type of giant caecilian just as has been speculated with the immense Minhocão?

Despite the lack of bones reported, caecilians would certainly account for the general appearance of the Fukuoka carcass. The segments would be perfectly mistakable for those of an earthworm. While caecilians do clearly have heads, since only a portion of the creature’s body was found, it seems reasonable to assume that would not be much of a problem in this case. However, again we are dealing with a burrowing creature unlikely to get too thick. As is the case with earthworms, caecilians do not get very wide in relation to their body length. An even bigger argument against a caecilian would be that they are not known to live in Japan at all. The closest we get with caecilians in Asia is the family Ichthyophiidae, or Asiatic tailed caecilians native to Southeast Asia. Of these, the most northern ranging species is Ichthyophis sikkimensis of northern India, and they are nowhere near the sizes reported. If a caecilian is behind any of the giant worm reports in Japan, it would be a new creature previously unrepresented in the country, as well as absolutely enormous.

Other possibilities include some sort of giant slug, however the presence of apparent segments seems to be at odds with a slug’s overall smooth skin. Some sort of gigantic centipede or millipede is also perhaps worth considering, however there were no legs reported on the carcass and the size would suggest a millipede or centipede unlike anything we now know of, perhaps beyond the physical limits of size for such a creature. When looking at these giant worm reports, one almost gets the feeling that we may even be looking at two different types of cryptid, giant worms in the case of reports like the Hyogo accounts, and perhaps something else with the Fukuoka carcass and other cases of truly massive worms. One wonders what we would have discovered if the whole creatures had been found in Kyushu, or if the witnesses had recovered some sort of specimen. As it is, we will likely never know.

Is there an unknown species of giant worm in Japan? There are currently around 6,000 species of earthworm known worldwide, including some of truly gigantic proportions. It seems reasonable to think that more will be discovered as we gouge, till and dig our way through remote patches of earth. Perhaps Japan is where the next giant species will be uncovered. In parting, let us consider the possibilities. Humans are exploring the oceans, rainforests, and other frontiers of the world, but what about into the world? What lies in wait for us wrapped deep in its burrow beneath the earth? It is clear that for some cryptids one need not look out to the forests, across seas, or up overhead, but rather down at the ground beneath our own feet.