Japanese Sea Lion

Posted by: Loren Coleman on November 8th, 2008

This is another guest blog by Brent Swancer.

One of the last known taxidermy specimens of Zalophus japonicus.

The Honshu wolf recently mentioned here is not the only Japanese mammal that has become extinct on the islands due to human influence. The Japanese sea lion, Zalophus japonicus, once roamed the waters around Japan, Korea, the Kuril islands, and the Southern tip of the Kamchatka peninsula.

The specific known range of the Japanese Sea Lion around Japan.

This sea lion reached sizes of up to 2.5 meters and 450 kilograms in weight and was especially numerous in the Sea of Japan, typically breeding on sandy beaches. Although they were often called “black sea lions,” 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.

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. 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 over-hunting and strained food resources due to over fishing. 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 harvested for a wide variety of other reasons. The skin was used for oil for lamps, internal organs for Oriental medicine, whiskers for pipe cleaners, and many specimens were collected for circuses. It is also said that soldiers would sometimes use the sea lions for target practice during World War II.

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 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.

The projected range of the Japanese Sea Lion on a world map.

Sightings of the cryptid Japanese Sea Lion continued into the 1960s and 1970s. There was even a juvenile specimen reportedly caught off Rebun Island in Northern Hokkaido in 1974. But none of these cases have been confirmed. Sources such as Wikipedia claim that the 1974 capture was the last confirmed specimen but this is 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 extinction was considered to have occurred. Therefore, this species was 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).

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, 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. 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.

Loren Coleman About Loren Coleman
Loren Coleman is one of the world’s leading cryptozoologists, some say “the” leading living cryptozoologist. Certainly, he is acknowledged as the current living American researcher and writer who has most popularized cryptozoology in the late 20th and early 21st centuries. Starting his fieldwork and investigations in 1960, after traveling and trekking extensively in pursuit of cryptozoological mysteries, Coleman began writing to share his experiences in 1969. An honorary member of Ivan T. Sanderson’s Society for the Investigation of the Unexplained in the 1970s, Coleman has been bestowed with similar honorary memberships of the North Idaho College Cryptozoology Club in 1983, and in subsequent years, that of the British Columbia Scientific Cryptozoology Club, CryptoSafari International, and other international organizations. He was also a Life Member and Benefactor of the International Society of Cryptozoology (now-defunct). Loren Coleman’s daily blog, as a member of the Cryptomundo Team, served as an ongoing avenue of communication for the ever-growing body of cryptozoo news from 2005 through 2013. He returned as an infrequent contributor beginning Halloween week of 2015. Coleman is the founder in 2003, and current director of the International Cryptozoology Museum in Portland, Maine.

24 Responses to “Japanese Sea Lion”

  1. DWA responds:

    Durn shame.

    As someone who comes on here talking about the validity of a huge bipedal ape (or two or three), I’m going to be the last one to say forget about the Japanese sea lion. But given the habits of sea lions, it’s kind of hard for one to hide out, just off the coastline of heavily-populated islands, for this long, with people having no particular reason not to report sightings of what looks like a species known to (previously, at least) exist. The sasquatch and the yeti – the thylacine, while we’re on it – have large territories to roam, large, well-vegetated swatches of which rarely see human visitation. Sea lions? Not so much. And this one seems to be so behaviorally similar to other sea lions that it was long confused with them.

    It seems a slight wee bit less than amazing that this animal held on as long as it apparently did, if you ask me. It lived right on the doorsteps of two of the world’s most avid marine-mammal hunting nations.

  2. dogu4 responds:

    Great report, Mystery Man. Knowing something about the Steller and California species of sea-lion, I find it hard to believe that once human harvesting of sealife is constrained so that sustainable populations of the original inventory of species can once again approach something of its historical levels, that neighboring populations of sea-lions, being very capable of swinning long distances, won’t be found in Japanese waters again…as surrogates perhaps but once again functioning in much the same way as the original populations did. Perhaps, following the strategies of those advocating restoration of our pleistocene inventories, we should help it along to see what kind of synergies come into effect in restoring these great biosystems to their full productivity which is something we should take seriously as modern management has shown diminishing returns.

    May I suggest a future article on the Japanese perspective regarding mammoths and the recent success with frozen mouse DNA. Cheers.

  3. Devonian responds:

    I’m honestly surprised it survived as long as it did, given Japan’s (and to a lesser extent, everyone else’s) tendency towards strip-mining the sea of everything remotely edible…

  4. corrick responds:

    Excellent posts Brent. Know I speak for many others in saying thanks.

    Was unaware of the recent DNA results giving Zalophus japonicus full species status. That makes it the 2nd historical pinniped to be declared extinct along with the Caribbean Monk Seal.

  5. squatchwatcher responds:

    I forgot to mention in the “Who are you, What do you like” blog that stories like this really interest me to. The information that Loren gives is so interesting.

  6. mystery_man responds:

    Thanks for the compliments about the post! I love sharing these things with everyone here.

    DWA- Indeed it is a shame. Not only are there no confirmed reports of this animal in recent days, there aren’t really many sightings at all since the 70s. So unlike the sasquatch, there really isn’t a whole lot to go on, not even claimed sightings. Also, you are right that there is nothing to point to this sea lion acting really any differently than other species (not the most inconspicuous animals, sea lions) and about them living along the coast of a heavily populated nation. I don’t hold out much hope for this one. However, there are some very remote areas in Northern Hokkaido and the Kamchatka peninsula, so the Japanese sea lion could possibly still survive there.

    Dogu4- It’s interesting that you mention the idea of reintroducing sea lions to the area, because there is apparently just such a proposal being thrown around by Korea. In 2007, South Korea announced plans to launch a multinational research venture by South Korea’s Ministry of Environment to search Korean, Russian, and Chinese waters for surviving sea lion populations. If they are not found, the plan is to relocate and introduce California sea lions from the United States. This could be very beneficial to the ecology of the area and Korea even hopes it will boost ecotourism. I’d like to do a post on the new Japanese research concerning cloning from frozen DNA, but I’m sure Loren will be on top of that one! 🙂 Fascinating stuff.

    Corrick- Thanks, I’m glad this interests you. Yes, the Japanese sea lion was concluded to be a distinct species quite recently after extensive genetic tests, and the same goes for the Galapagos sea lion. These tests closely supported the morphological finds that had already pointed to this sea lion being a distinct species.

  7. cryptidsrus responds:

    I also would like to congratulate you on a great posting, Mystery_Man!!!
    Maybe, just maybe, there’s one still out there. Highly unlikely, but other supposedly “unlikely” animals have been found. (Fingers crossed). 🙂

  8. corrick responds:

    Although I don’t have much hope pockets of Japanese sea lions still exist, and even less for Steller’s sea cow or the Caribbean monk seal, it isn’t impossible.
    Marine mammals have shown a remarkable ability to rebound despite man’s best attempts to exterminate them. The story of the Guadalupe fur seal serves as a good example. There are now close to 130 accepted historic species of cetaceans, pinnipeds and sirenia. Of those, only Steller’s sea cow, the Caribbean monk seal, the Atlantic population of Gray Whale, the Japanese sea lion and most recently the Yangtze river dolphin are considered extinct. Course that list may grow quickly in the near future.
    Anyway, if any mammals “reappear from the dead,” history says some species of marine mammal is your best bet.

  9. red_pill_junkie responds:

    Thanks for the article, M_M! 😉

    I have a question, though: Did this animal have an important role in Japanese folk tales, like the fox? Seems to me that if a creature is a part of your cultural tradition, it is less likely you’d bring it to extinction.

  10. mystery_man responds:

    red_pill_junky- The Japanese sea lion did not have any particularly prominent role in Japanese folklore as far as I’m aware. There were a few local myths about the presence of the sea lion being a sign of good fishing or good luck, and some of these areas even tried to preserve the animals, but not much beyond that. It was mostly seen as a marine resource and for awhile prior to the outbreak of World War Two in 1941, seal hunts were subject to government approval. There were even fishery houses built expressly for the purpose of harvesting the sea lions.

    Sadly, I’m not sure it would have done much good even if the Japanese sea lion was an important figure in cultural traditions. Look at what happened to the Honshu wolf, and it was revered at one time. It really is a shame.

  11. dogu4 responds:

    Very interesting.
    I notice that the superfamily of sea lions span all the world’s oceans except the North Atlantic. Strange, eh? Any fossil record of them there?

  12. corrick responds:

    Not unless they’ve surfaced very recently. Which is why the classic zoological mantra has always been eared seals evolved in the northern Pacific, phocids in the northern Atlantic.

  13. mystery_man responds:

    Dogu4- I’m not completely sure of the fossil record of the sea lion in Japan. I do know that the Japanese species is thought to have diverged somewhere between 2.2 and 2.5 million years ago. The species probably branched out to other areas of the Pacific for any number of reasons, ending up in Japan, Korea, and Russia, where speciation occurred. So my guess would be that yes, there is likely fossil evidence of them in Japan.

  14. dogu4 responds:

    Thanks Mystery Man…and Carrick. Considering the geological past it’s still puzzling to me that the North Atlantic has no record of otariid Pinnepeds except for a few contemporary reports to what were likely to be escapees from captivity or as the result of human intervention.

    The idea that because the eared seals evolved in the Pacific and just havent made it to the North Atlantic may be true, and I can understand it as the most likely explanation, it just seems hard to swallow, considering that from time to time sea lions will actually eat harbor seals and the family of sea lions seem to have adapted to such wide ranging and far flung habiats across the oceans.
    Perhaps some of the answers lie just a few hundred feet below the current sea level, an area deucedly difficult to examine at the current time with our current underwater technolongy…but that might change.
    At any rate, the fact stands in curious relationship to the depopulating and partial re-population of North America at the end of the Pleistocene.

    Anyhow, thanks for sharing that knowledge. I remain both intriqued and engaged and feeling that there’s lots of mystery yet to be revealed. cheers.

  15. mystery_man responds:

    Dogu4- I’m sorry, it seems that I totally misunderstood your question. I thought you were asking about fossil remains in Japan when in fact you were asking about the Atlantic.

    To the best of my knowledge, there is no evidence of sea lion fossils in the Atlantic, as corrick said. I do think you have a good idea that fossils may be buried under the surface in areas that are beyond our current abilities to efficiently study. Also, I agree that sea lions could have feasibly branched out beyond the Pacific and into the Atlantic. They are indeed pretty adaptable and have settled into far flung habitats throughout the Pacific, such as Japan and the Galapagos Islands. I wouldn’t totally discount the possibility of them making their way into the Atlantic, but there is no evidence that I know of such a migration at the current time.

    It would certainly be interesting to see what sort of fossils would turn up through such an avenue of research as you describe.

  16. dogu4 responds:

    Thanks Mystery Man…I recognized that you were addressing the question from the aspect of Japanese Sea Lions’ natural history…and appreciate it.
    It’s just that it seems there is something peculiar from my point of view regarding the sea lions’ singular and conspicuous absence..not from the Atlantic…but only from the North Atlantic. Just another mystery…cheers.

  17. mystery_man responds:

    Dogu4- Yes, that’s what I was referring to, the North Atlantic. I agree with you, it does seem conspicuous. I’d be more than interested to hear some of your ideas concerning this mystery in the Atlantic. I also share an interest in animals such as the Steller and California sea lions (with a specific interest in the Japanese and Galapagos varieties), and I am always interested to hear different takes on the possible evolutionary routes and habitats of these animals in different areas.

  18. mystery_man responds:

    It might also help to just say we are talking about otariids (eared seals) in general instead of using the common name “sea lions” for some varieties in order to avoid any confusion people might have concerning ranges and habitats.

  19. mystery_man responds:

    It might also help to just say we are talking about otariids (eared seals) in general instead of using the common name “sea lions” for some varieties in order to avoid any confusion people might have concerning ranges and habitats.

  20. dogu4 responds:

    Totally agree regarding the references to otariids (eared seals) in contrast to “true seals”.

    As for my notion explaining the conspicuous absence of the sea-lions from the North Atlantic, I’m compelled by the recent theories regarding a significant meteor impact 12.9KYA over northeaster North America and consequently the North Atlantic. It’s off topic a bit but the theory is nicely explained by the researchers at last years AGU meeting and recorded on youtube here:

    Also, I read where the genetics of the current megafauna in N. America suggests that they re-populated the continent sometime in the not too distant past, which they’d naturally do, some from Eurasia (wolves, bears and caribou, etc), and some from Central America (mountain lions and bison, etc). Sea lions, not being creatures of the ice, like certain seals and walrus, would be blocked from an easy northern return, and the since the isthumus of panama has been in existence over the last 3 million years, they couldn’t use a tropical route.

    Anyhow, it’s merely an exercise in speculation but I’ll keep my sensors tuned for news of otariid fossils from the North Atlantic in the mean time. cheers

  21. mystery_man responds:

    Dogu4- Interesting stuff. Yeah, I won’t get it too off topic here but the movements of animals and geographical factors involved is fascinating to me as well.

    I find it very curious that otariids would not branch out into Northern Atlantic waters simply because they are so widespread pretty much everywhere else and are quite adaptable. The sea lions of the Pacific for example have moved out and adapted to a wide variety of far flung habitats across the ocean where they have proven to be successful (when humans aren’t harvesting or killing them as the case with the Japanese sea lion). Otariids are fairly well established in some Southern Atlantic waters such as in South America and the Falkland Islands in the case of the South American sea lion Otaria flavescens, or Southern Africa in the case of the Cape fur seals and South African fur seals. It seems to me that there has been enough time for them to populate the North Atlantic regardless of the geographical limitations of the past. The Atlantic seems to offer enough resources and favorable habitats for it to have made sense for otariids to expand to take advantage of these resources. I am particularly interested in what the biological and ecological reasons for their conspicuous absence there might be. This is fascinating to speculate about.

    Anyway, great discussion.

  22. ejjury responds:

    Oh Japan, when will you quit killing things off (not that we don’t do just as much killing)?

    I guess I am still bitter about illegal whaling, the killing of mass numbers of dolphins (even though I dislike them), the overfishing that is done, and the light pollution from those fisheries.

  23. ewargo responds:

    Really interesting discussion.

    This isn’t fossil evidence, but perhaps worth considering: One of the less common Pictish symbols (Dark Age Scotland) is sometimes called a “dog’s head” and sometimes called a “seal” — it has front flippers but a distinctly dog-like head with small, swept back ears. When I first saw it, my immediate thought was “sea lion,” but a quick check revealed the curiosity that you are all discussing: the conspicuous absence of sea lions from the North Atlantic. Could the sea lion have been hunted to extinction in those waters in the Middle Ages?

  24. dogu4 responds:

    Ewargo; thanks for that interesting bit of lore. I agree that it is still something odd, or better yet, cryptic. I actually sent an email to the Smithsonian’s specialist in the area, and he confirms that there are no fossils of sea lions identified in the North Atlantic and agrees it’s curious but without any evidence to the contrary it must be considered just a peculiar aspect to this genus’ pattern of radiation and speciation. But, it’s early in the new year, who knows what’s under the next rock? Cheers to all.

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