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The Japanese Sea Lion and River Otter: Extinct or Not?

Japan, as an island nation, has a sensitive ecosystem that has seen its share of animal extinctions over the centuries. Many truly unique species of animal who once called this place home have been erased off of the face of the earth, and these are not only merely small species that are easy to miss. In addition to the Japanese wolf, which I have covered here on Mysterious Universe before on several occasions, indeed, this land was once home to two other rather significant and large animal species which went extinct yet seem to still manage to incite debate as to their true status as sightings pop up from time to time.

The Japanese sea lion, Zalophus japonicus, once roamed the waters around Japan, Korea, the Kuril islands, and the Southern tip of the Kamchatka peninsula. This majestic sea lion reached sizes of up to 2.5 meters and 450 kilograms in weight and was especially numerous around the Sea of Japan, typically breeding in large numbers on sandy beaches. Although they were often called “black sea lions” due to their dark coloration, they were not melanistic. Males were typically a dark grey or brown in color and females were a lighter pale grey. A mid-19th century text also described some female specimens as being straw-colored with darker colored underbellies.

One of the very few known mounted specimens of a Japanese Sea Lion

In 1850, these sea lions were wrongly described as being Steller’s sea lions, and in later years they were thought to be a subspecies of the Californian sea lion, Zalophus californianus. This taxonomic classification persisted until very recently, when zoologists took a good look at the sea lion’s morphology and DNA. Through further examination of bones, it was found that the skulls of the Japanese sea lion were proportionately wider than that of the Californian variety. In addition, genetic tests turned up convincing molecular evidence that when taken in conjunction with the morphological differences show that indeed the Japanese variety were a distinct species, with the two species are thought to have diverged around 2.2 million years ago during the late Pliocene.

The Japanese sea lion faced a long history of relentless over-hunting and strained food resources due to over-fishing within its habitat. An 18th century Japanese encyclopedia known as the Wakan Sansai Zue described the meat of these sea lions as not tasting very good, but they were nevertheless harvested for a wide variety of other reasons. For instance the skin was used for oil for lamps, internal organs for Oriental medicine, whiskers for pipe cleaners, and many specimens were collected for use in circuses or traveling animal shows, where they proved to be most popular. It is also said that Japanese soldiers would sometimes use the sea lions for target practice during World War II, where they would be picked off right from the beach, and they were so numerous that it didn’t seem to matter much. No one thought much of their prosperity or future. Over 3,200 animals were harvested at the turn of the century, and by the 1930s only a few dozen individuals remained. By the 1940s they were all but extinct. The last known confirmed sighting of these creatures was a group of 50 to 60 individuals on a small rocky island known as Takeshima in 1951, and the Japanese Sea Lion was declared extinct by the late 1950s.

However, sightings of the cryptid Japanese Sea Lion continued well into the 1960s and 1970s, proving they were not quite gone yet. There was even a juvenile specimen reportedly caught off Rebun Island in Northern Hokkaido in 1974, but none of these cases have been confirmed. Numerous sources such as Wikipedia claim that the 1974 capture was the last confirmed specimen, but this is actually incorrect. Although the last known sighting was the one on Takeshima Island in 1951, the Japanese Sea Lion was not officially declared extinct until almost 40 years later, with the date fixed in the 1950s, when the actual extinction was considered to have occurred. Therefore, this species was actually finally given its extinct status on the IUCN Red List of endangered species in 1990 (despite the fact that it had long been considered extinct by zoologists).

Illustration of a Japanese sea lion

Some people believe that the Japanese Sea Lion might still be holding on out there, but it seems doubtful. There are not many reliable sightings after the 1970s, although they do filter in from time to time, and there have been extensive marine wildlife studies done in the areas they once inhabited. I tend to think that they likely persisted past the 1950s, but I’m afraid this is one species that might truly be gone now. Many of the sightings of supposed Japanese sea lions in recent years have been chalked up to being misidentifications of other species of seal or sea lion that have wandered into these waters. If they do indeed still exist, I think the most likely places to find the surviving Japanese Sea Lion would be the remote areas of Northern Japan and the Russian Kamchatka peninsula.  here has been some some sad animal news in recent years in Japan, when the Japanese river otter (Lutra nippon), also known as Lutra lutra whiteleyi and the  日本獺 or 日本川獺, the nihonkawauso or nipponkawauso in Japanese, was declared extinct by the Japanese Ministry of the Environment on August 28, 2012. The announcement came after several decades of searches for any possible remaining specimens, although they are allegedly sighted all of the time.

The Japanese river otter was a nocturnal predator, endemic to Japan, which reached 26 to 30 inches long at maturity. Inhabiting mostly midstream and downstream regions, it was once found abundantly throughout Japan. The number of Japanese river otters decreased rapidly beginning around the Meiji and Taisho eras, due to extensive hunting for its fur and liver (which was used as a medication for tuberculosis) and further continued with habitat destruction, water contamination, large scale river construction, and even attacks by domestic dogs. Although the otters were designated as a Special Natural Treasure in 1965, the steady rate of decline continued unabated. The only known captive specimen was purportedly kept at a zoo in Ehime prefecture from 1956 to 1969. It is widely believed to have been one of the last of its kind. The last known officially verified sighting of a Japanese river otter was made in 1979.

Despite the lack of any confirmed sightings past 1979, the otter was listed as critically endangered and thought to only be present in the Southern area of Shikoku island, a fraction of its former range. Encouraged by numerous further sightings of possible survivors, official searches have been commissioned by both prefectural governments and non- governmental organizations in recent years in order to find any remaining specimens and hopefully salvage the species if it was still out there. The search was unsuccessful in locating any remaining otters.

This brings us to the present, August 29, 2012, when the Ministry of the Environment finally concluded that the Japanese river otter no longer exists, although there are quite a few eyewitnesses who have continued to see them, particularly in Ehime Prefecture, and who would perhaps disagree. Indeed, not everyone is as pessimistic as the Ministry of the Environment. Yoshihiko Machida, a professor emeritus at Kochi University told the Japanese newspaper, The Mainichi,  that he remained hopeful that the Japanese river otter still survives. “There was a case of otter droppings being confirmed in 1999. I think it is possible that they still exist, and I want to continue my investigations,” he said.

Stamp featuring the Japanese River Otter

I tend to agree that the extinction announcement may possibly be premature. It is first of all important to remember that a species being officially declared extinct is not necessarily the final word. History is full of examples of species being found to exist long after their supposed extinction dates, in some cases very, very long after (Coelacanth anyone?). The process of going extinct is typically a gradual process, with populations or scattered individuals often hanging on in remote habitats for years, and it is difficult to gage at exactly what point we can say with certainty that a species has gone from the face of the Earth. Usually, the decision to list a species as extinct stems largely from a lack of verified sightings or physical evidence of the animals over many years, but these decisions to claim a species as extinct have been defied time and time again.

In the case of the Japanese river otter, although the last confirmed sighting is set at 1979, the fact is that there are still many unconfirmed or unverified sightings that continue to this day, some of them in areas of their former range where they have long been considered gone.  Some of these unverified sightings may perhaps be misidentifications, but they are curious nevertheless. The exotic pet trade in Japan is a booming business and there have been several cases of muskrats and even a nutria being found in the wild here. It could be that the otter sightings were of something like this, however I do not feel comfortable dismissing all sightings as such. It seems to me worthwhile to pursue these persisting sighting reports of otters that still may remain.

In addition to sightings reports, there were droppings of an otter found in 1999 in Ehime Prefecture. This is significant because the otters had a very specific diet of shrimp and other aquatic organisms, and has the type of unambiguous scat can be readily identified as being that of an otter. Since it  can be demonstrated that the droppings were in fact those of an otter, the droppings found in 1999 indicate the presence of at least one individual well past the last known sighting. 1999 to 2012 is not a large amount of time when talking about the gradual extinction of a species, so the droppings, in conjunction with continuing sightings reports, give us more reason to think that some of these animals may continue to persist in the wild.

River flowing past Ozu Caste, in Ehime Prefecture, Japan

Another factor to consider is that contrary to the common image it has of bustling, neon showered metropolises, Japan has vast untamed areas, with many remote river habitats where a small population of otters could still remain undetected, and the searches carried out by national and prefectural governments do not seem to have been particularly aggressive or all encompassing. Most of these searches were focused on the areas the otters were last known to inhabit, namely on Shikoku island, rather than an all inclusive search of the entirety of the otter’s former domain. The problem with this is that even if the otters have indeed disappeared from their last known habitat, they may have remained in far flung areas of their historical distribution. This is further supported by sightings of the creatures in areas of the otter’s range outside of Shikoku.

The remoteness of some of the terrain and size of the Japanese otter’s former range suggest to me that some of the animals may have evaded detection throughout these searches, particularly in harder to reach habitats. To me, a complete absence of sightings and no physical evidence whatsoever would be more indicative of a conclusive extinction, but this is not the case with the Japanese river otters. Considering the continuing sightings, the discovery of droppings, and existence of suitable, remote habitat within a large former range, I feel that we should not necessarily close the door on this species just yet. I would add, however, that if it still exists, the population of these animals is likely very small and clinging precariously to existence. It may well be the case that there are not enough individuals to maintain a stable breeding population, which would therefore make the species more or less functionally extinct.

One of the very few existing photos of a living Japanese River Otter

Interestingly, the Japanese River Otter is connected to cryptozoology in more ways than one. It is thought by some in cryptozoological circles here in Japan to be an explanation behind the sightings of another Japanese cryptid, the legendary Kappa, which is a sort of bipedal, frog-like creature thought to inhabit Japanese rivers. In addition, the otter has been proposed as a possible explanation for the Matsudodon, a mewling,  aquatic cat-like cryptid that was often spotted frolicking in the Edo river near Matsudo-shi (near where I live now, interestingly enough) in the 1970s. In addition to the Japanese river otter,  the horseshoe bat of Okinawa, a bird species, an insect species, and a shellfish species were also declared extinct in the recent announcement. The Japanese subspecies of black bear was also declared extinct on the island of Kyushu, where it has not been seen since 1957, although it should be noted that the subspecies is not extinct in other areas of Japan and has continued to be sighted even in Kyushu, defying its extinct status.

So do these species still exist or not? It is hard to say for sure. Absolute extinction is not always something that can be reliably measured, and there are certainly numerous species that have come back from the dead after decades, centuries, or even millennia, to prove that we were wrong and that they have beaten the odds. Perhaps the Japanese sea lion and Japanese river otter continue to exist somewhere out there, defying their extinct status. There are certainly enough reports and accounts that suggest so. Whether they are out there or not remains to be seen, but no matter what the answer to that question may be, they certainly paint a rather sad picture of the fall of a species, highlight the problem of extinction, and make us wonder what the future of our planet may hold for its biodiversity.