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Japanese Giant Salamander

Japan flag. Japan's Natural History: The Japanese Giant Salamander

The Japanese Giant Salamander: Gross Grails and Salamander Tales

Secretions | Tracking The Giant Salamander | Books on Giant Salamanders | Giant Salamander Facts

Mark Brazil

Japanese Giant Salamander.
A Japanese Giant Salamander Andrias japonicus in shallow water, lying in wait for prey to swim past.

The naked Bull-dog Bat, denizen of Southeast Asian cave-systems is not, in my opinion the ugliest creature on earth, though it has that reputation.

Neither is the Naked Mole Rat, nor the Aardvark, though I have heard similar claims for both. No, the grand title goes to a creature, a young one of which, I misguidedly handed to a naive television producer. The response was astonishing (on both their parts!).

The human response was unexpected - from a natural history producer that is. There was an instantaneous squeal, a tightening of the shoulders, the arms whipped out and up, and the cupped hands on which the ugly creature lay but briefly, acted as launch pad! The creature's response was, initially at least, not so unexpected. Gravity took over quickly where human hands left off and it returned to its rocky riverside habitat somewhat precipitately. I was berated (by the producer) for being more concerned about it than her, but "it", a salamander of an exceptional sort, was an endangered endemic species restricted now to very few parts of Japan!

I had been intent on tracking it down for over a decade, and its next response had already totally captivated me.

A lifetime's interest in natural history did nothing to prepare me for my first in-depth contact with large amphibians, and this salamander, a giant of its kind, did something that neither birds nor mammals can. The impact did not (thank goodness) kill it, but shocked it was, and in an instant it came up with a unique autonomic physiological response. It turned white. Not the blood-draining-from-the-face kind of whiteness, but an all-over sticky kind of whiteness. Its entire skin surface was exuding an acrid milky substance.

Japanese Giant Salamander.

Japanese Giant Salamanders move slowly and sluggishly on the rare occasions when they leave the water.

Giant Salamander's Secretions

The secretion of an amphibian's granular, or serous, skin glands are at best noxious and at worst toxic. Best known are the toxic steroidal alkaloids produced by certain dendrobatid frogs. Phyllobates terribilis is the record-breaker here; with some toxic enough to kill c20,000 twenty-gram white mice (talk about overkill!) or several adult Homo sapiens.

Salamanders can pack a punch too, some producing neurotoxins, and others alkaloids that cause muscle convulsions. Thankfully, giant salamanders don't, for I couldn't resist touching it to find out more. The sensation reminded me of childhood days sticking pieces of card together with rubber solution glue. The secretion partly bonded to my skin, but then rubbed off easily forming drying rubbery lumps.

My skin didn't react, but my nose certainly did! The most ugly creature on earth was exuding the foulest smell I had ever encountered, a description of which is virtually beyond the English language. Imagine, if you will, the rankest smelling public urinal crossed with the stale smell of certain 'bodily secretions' and you are just part way there. I imagined that even diluted in water, that acrid secretion might be enough to deter a potential attacker.

Japanese Giant Salamander.

A giant salamander's blotchy skin patterning renders them highly cryptic underwater on rocky and gravel shoals.

Tracking the Giant Salamander

You may well wonder, why on earth such ugliness and why such smells had drawn me like a moth to a flame. Tracking down the Japanese Giant Salamander had become something of an obsession. It had begun over twelve years earlier when I had first confused Japanese folk tales about the mysterious river imps, the Kappa, with fourth- or fifth-hand stories of salamanders to dwarf all others.

For several years I dismissed them as a mythical oddity, but then while planning a high altitude trek in the Japanese Alps, in search of various alpine plants and birds, I stumbled on the writings of the Reverend Walter Weston. It was he, a century earlier, who had popularised hiking and climbing in Japan. In his writings, such as the monumental Mountaineering and Exploring in the Japanese Alps published in 1896, he described in detail, how his guides had hunted for food and how he lived off Japanese Serow and Japanese Giant Salamander meat.

If he had eaten them, then they were certainly not mythical, at least not a century ago. I was back on the scent, though it proved a tortuous trail that I was following, and I had no idea then that the scent was foul! I spent my whole time in the Japanese Alps in 1984 not even knowing where to look for them, and returned to my research on Japanese birds rather defeated by salamanders.

As the Music Quiz might put it: What draws together medicine, deportation from Japan, Noah's flood, and German myth busting? The answer, obviously, is the Japanese Giant Salamander. Philippe Franz Baltasar von Siebold, a medical adviser to the Dutch East India Company in Nagasaki, was deported from Japan in 1829 (for collecting maps!). A naturalist and inveterate collector, he carried back to Europe the very first giant salamander to be seen alive outside Japan.

Siebold described it in the great collaborative work Fauna Japonica (1833-1851) and in so doing shattered a post-diluvian delusion. A century earlier, in 1726, the skeleton of a 'child' had been found in Germany, a child who was believed to have died at the time of The Biblical Flood. That discovery had been taken as irrefutable proof of the truth of the biblical tale. Astonishing similarities between that skeleton and Siebold's specimen were ultimately to confirm heretic suspicions that it belonged to an animal; it was, in fact, a Cretaceous fossil of Andrias scheuchzeri, an extinct relative of the Japanese Giant Salamander.

Over a fistful of years I continued to quiz every Japanese naturalist I could for rather more up-to-date "intelligence". I was, in a way, getting closer. Some knew nothing of the O-sanshyowo at all; others believed that it was exceedingly rare, but still survived. Finally my Japanese naturalist mentor, Takada Masaru, suggested a photographer, whom he had heard had photographed one. I was homing in, or so I thought! The Japanese-language not being my strong point, it was some time before I plucked up courage enough to phone Egawa Masayuki, but he couldn't have been more helpful.

Although he hadn't photographed them in the wild, he had seen them in an aquarium at Nikko, and had tracked down their range to a region of western Honshu, but had taken his own quest no further. Western Honshu was bad news as far as I was concerned, as I was living over a thousand kilometres further north in Hokkaido. Japanese Cranes, Steller's Eagles and Blakiston's Fish Owls were virtually on my doorstep, but giant salamanders were still a world away.

Japanese Giant Salamander.

The giant salamander's mouth stretches the entire width of its head, its eyes though are tiny white spots. Note that the forelimbs have just four digits.

So for several years wild giant salamanders were on my back-burner (metaphorically-speaking), but when tracking them in the field was not possible, I was not idle and spent hours in libraries trying to trace references.

Trying is the operative word. It seems that during the last century giant salamander attracted about as much research interest as the dragon or the phoenix. Text after text repeated (or contradicted!) the same information, or gave none at all, and the very latest (and the largest) text book on Amphibian biology I found, gave the record-breaking giants minimal space and relied almost entirely on material over 60 years old.

Books on Giant Salamanders

Books purporting to cover the whole subject of the world's herpetofauna, gave them but a few lines, and I began to realise that I was on the track of a virtually forgotten animal. It seemed, in fact, that nothing of real significance had been discovered since the 19th century! Scouring libraries for the world's largest amphibian was hardly more productive than scouring the Japan Alps. I was, however, finding out how little was known, and my drive to see one was heightened. A surprising break through came when I discovered, by chance, an older, fact-packed source, Gadow's The Cambridge Natural History. Amphibia and Reptiles published in 1901, gathering dust on the shelves of the Otago University Library in Dunedin, New Zealand. At last I had found a genuine resource.

My personal experience of salamanders was limited to small newt-like creatures in Europe, so when I first read that inspiring prefix Giant I had blithely imagined something perhaps twice newt-size. But then I realised that if the giant salamanders of Asia were bigger than the American hellbender, and if that reached 70-75 cm long, then the Asian species had to be really huge, or was it all just a tall tale!

Japanese Giant Salamander.

Exceedingly slow growing, this small captive salamander is already six years old.

Researching Japanese Giant Salamanders.

Japanese Giant Salamander researcher in full gear for wading up riverine habitat at night.

Some of the modern texts I consulted told tales that seemed almost as mythical as the folk tales that had first misled me; of salamanders living to over 50 years old (though after laughing at that one I was to discover that Siebold's specimen had not died until 1881, aged over 52 years!), growing to over one and a quarter metres, and being "baited with a fish, a frog, or several earth-worms" and "captured by fishermen with hook and line", for food. Now who would want to eat salamander! Yet several sources claimed, no doubt indirectly referring to Gadow, that "the giant salamander is much esteemed for its very palatable flesh." It supposedly tastes of chicken. But if the tales were true, then this was the mother of all salamanders; on an amphibian scale for it to be to a newt, what a Komodo Dragon is to a sand lizard!

It was one thing to realise how big, how rare and how little known the O-sanshyowo was, but I still had to turn my myth in to a reality. Year after year I traversed Japan, but each time my work forced me to either bypass salamander range or to pass through at the wrong season. There was nothing for it, but to make a special journey, my personal quest for the ugly grail.

Egawa-san had told me, by now years previously, that he believed the salamanders spawned in August and that their eggs hatched in late September, and that was therefore the best time to search for them. With that as my only clue, I set out again, more than a decade after my first search in the Japanese Alps, in search of the real giant. Various leads had suggested Himeji as a starting point and I was given an introduction to the director of the aquarium there. By an amazing coincidence, the fact that he had moved on proved good (not bad) luck, because in his stead I was to meet someone who had made a prolonged study of the animal of my quest. When could I visit, was his question! As soon as you are available, was my answer.

Japanese Giant Salamander specimens in jars.

The first specimens of the Japanese Giant Salamander, sometimes known as Megalobatrachus japonicus, that I encountered, were pickled eggs and young in jars.

After over a decade on the trail I found myself one dark balmy September night listening to the chorus of crickets, watching the constellation Orion rise from behind a forested ridge, and being strapped in to rubber chest-waders, with a lamp being fastened around my head. With a long staff in my hand I was off, clambering up a rocky-bedded gushing mountain river, with pools and potholes deep enough to swallow me whole. No wonder I hadn't found salamanders in the Japanese Alps! But now I was following in the footsteps of the world expert on the species, a man who's work in Japanese seems to have been missed by the English-speaking world.

Tochimoto-san's enthusiasm and agility belied his age, and though fifteen years his younger, I struggled to keep up in the fast water, as I flashed my hand beam in to the shallows, under rocks and on to gravel bars, searching, searching

Then suddenly, there in the dappled water, resting on a submerged gravel bar I saw it. My first giant salamander! The thrill is indescribable. I was in sight of my holy grail. Even through the water I could make out its massive blunt head and stout body, the thick, fleshy, laterally compressed tail sporting a fin, it seemed enormous.

With a scoop and twist of the net we carefully extracted the first specimen of the night, and at long last I was able to examine a wild Japanese Giant Salamander in the flesh. Thrilled with excitement, my mind was filled with thoughts of Siebold, the first live specimen in Europe, and of Weston and his tales of eating this endemic species.

But this was science and we had a task to perform, to check, measure, and perhaps identify the individual, before releasing it in to its river. There was little time for me to dwell on the grossly solid rubbery mass of the animal or its minute "piggy" eyes as we transferred it from net to bag for weighing, then to tray for an examination. The process was to check each limb in turn, for these are fleshy, functional, and have four fingers and five toes, or they should have!

During aggressive territorial fights these, and parts of the tail, are often bitten off. This feature provides the researcher serendipitously with a further means of individual identification to back up photographic records of the individually distinctive patterns on the top of the head and particularly on the side of the tail. Several we caught had missing digits, and one had lost most of two limbs and another had teeth marks on its tail.

What struck me most powerfully though was, apart from the sheer size and immense ugliness of the creature (though at a little over 50cm, this was but a 'small' one) was the massive, irregularly shaped fold of skin along the sides of its depressed body, which I assumed served as an assisting aqua-lung. I was warned clear of the head end, and a quick glance told me why.

The mouth seemed to split the wide, flattened head in half. With little effort a large adult could have opened up its mouth sufficiently to take in most of a human hand. Though the curved rows of saw-like teeth are simple in form, they are as sharp as a Japanese sword and easily capable of slicing off a human digit or two. I felt a twinge of fear, a healthy respect, and not even a trace of envy for the smaller salamanders, fish, crayfish and invertebrates sharing its riverine habitat - and forming its prey.

Japanese Giant Salamander.

Giant salamanders inhabit cold, fast-flowing rivers with shallow shoals where they can hunt and occasional sections of muddy bank or jumbled rocks where they can hide during the day.

A kilometre or more up river, several catches later, and even deeper in to the night, I held in my hands a real giant, both rubbery and slimy. At 99cm from snout to tail tip it was our largest encounter, weighing just over six kilograms. Yet that was probably nowhere near fully grown, as Japanese giants have reached lengths of up to 160 cm! I tried to imagine one that big in my hands, but even that would have been a dwarf compared with some prehistoric amphibians the largest of which, Mastodonsaurus, had a skull that was 100cm long.

Their weights tend to match their size, though individual weights vary enormously depending on their sex, and on food availability. One we caught was clearly extremely emaciated, the bones in its tail easily felt, and its head appearing unnaturally large on its body.

Others were sleek and fat; the smallest was just 25 centimetres long, and only barely an adult (see box), and the largest was that 99cm behemoth. Specimens weighing over ten kilograms are not unheard of, while five kilograms is about average for well-grown individuals in the region of 85cm long. In captivity, however, they have been known to go for over a year without eating at all, so growth rates and ages are difficult to calculate.

To give you a real sense of scale, think of the Japanese Giant Salamander (JGS) as an otter, and quite a large one at that. It occupies an otter's habitat, eats an otter's food, and differs only really in that it moves slowly waiting quietly for its prey to swim past, rather than chasing it down (the other minor differences I won't go in to!). Their eyes are tiny, almost an after thought in their monstrous heads, and so small that they must be of little significance during predation.

Prey are not pursued, but caught by waiting for a close approach. A swift lateral lash with the head, and the prey is seized with the teeth. From the time they reach 40-50 cm or more in length JGSs are the top predators in their riverine ranges. As larvae and as youngsters, however, they fall prey to everything from kingfishers and herons, to fish and larger cannibalistic salamanders.

By the time they are even half grown, however, they are wreaking revenge on the fish, they dwarf the kingfishers, and the herons just don't dare. As they reach mature size the only real threat to them is another even larger, or more aggressive male (or a human river engineer).

Japanese Giant Salamander Habitat.

Natural rivers, with a steady flow of cold, fresh water are essential habitat for the nocturnal giant salamander.

One of the animals we caught that night bore a wound that I imagined must be fatal, and which was the largest fresh wound "Mr. Salamander" had ever seen. Its neck and throat were cut open, from one side to the other right through to the oesophagus. Blood soon filled the examination tray. Although, their healing capacities are phenomenal (I saw some individuals which their scars testified had clearly survived massive wounds), this one #334 (first identified ten years and four months earlier) did not last the next 24 hours, and was found dead in the river the following day.

Although territorial aggression is not common among salamanders generally, Japanese Giant Salamander males are highly territorial, attacking and driving away all conspecifics except gravid females. The badly lacerated animal we caught, had from the curved nature of its wound, been caught by the head by a much larger male and sawed at until somehow it escaped! Apart from deaths caused by human activity, fighting between males seems to be the most significant cause of mortality with the overwhelming majority dying during the breeding season in September, most by their heads being severed!

The closely related Chinese Giant Salamander is even less well known than the JGS, and is under threat from hunting. In Japan, though, hunting was made illegal in 1952 when the Japanese Giant Salamander was made a special natural monument.

The main threat to them now, and the factor which continues to reduce both their range and their numbers, is the relentless impact of river engineering projects leaving rivers more akin to storm drains and exceedingly giant salamander unfriendly. Yet an unaltered salamander river could hold in excess of 350 individuals throughout their acceptable altitudinal (or is it temperature?) range. In my first night in their range, by far the most exciting night spent in search of wildlife of my life, we were able not only to realise my dream, but also to examine eleven of the world's ugliest creatures in detail.

Japanese Giant Salamander.

Cryptically patterned, the Japanese Giant Salamander appears rock like in its natural habitat, its eyes barely as large as the warty bumps on its skin.

Yet, not everyone is inspired by amphibians, even the great Linnaeus is well-known for being prejudiced against them and those who studied them, and as Gadow wrote so succinctly for the time (1901): "One reason for the fact that this branch of Natural History is not very popular, is a prejudice against creatures some of which are clammy and cold to the touch, and some of which may be poisonous."

Perhaps if more people encountered an abruptly shocked Japanese Giant Salamander exuding acrid-smelling rubber-solution glue at close quarters, they might be even more prejudiced against amphibians than Mr. Gadow!

Giant Salamander Facts

Today there are just three living members of the family Cryptobranchidae. Two giants in Asia, one in Japan and the other in central China, and the hellbender, Cryptobranchus alleganiensis, of eastern USA.

Though now confined geographically to very limited areas, the fossil record shows that giant salamanders were once common even across Europe (in the Oligocene, Miocene and Pliocene), North America (Miocene), and eastern Asia (Pliocene).

The Japanese Giant Salamander (JGS), Andrias (or Megalobatrachus) japonicus , the world's largest amphibian, reaching lengths of up to 160cm, can be separated from the closely related, but smaller, Chinese Giant Salamander (CGS), A. (or M.) davidianus , because whereas the JGS has pale brownish skin with dark brown spots, the CGS has darker skin with paler spots. As adults, JGSs have individual warts irregularly arranged on the head and throat. Adult CGSs have warts too, but they occur in pairs. One wonders just how big the CGS would grow if it were not still caught for food in China. Fossil species of Andrias, however, hold the record, having reached lengths of 2.3 metres!

Both Asian species differ from the much-smaller hellbender, in having closed spiracles as adults and two gill arches on either side of the gill cavity. The flatter-bodied hellbenders have an open spiracle (sometimes just on one side) and have four gill-arches on each side of the gill cavity.

The three primitive giants are unusual among salamanders, in that they are all obligate neotenes (that is they experience delayed somatic development combined with precocious reproductive development, so that they attain reproductive maturity while retaining the appearance of a larval form). They never complete a full metamorphosis, although the adults lose their gills, but they retain larval teeth and never develop eyelids. The Cryptobranchids are also unusual in that they all continue to live virtually entirely in water even as mature animals.

The JGS leads an essentially solitary life. They hide away in shadowy spots under rocks or tree roots in swift-flowing, cold water streams or rivers no wider than a few meters, at altitudes between 200 and 1,000 m, and which don't freeze over in winter.

The female's role in reproduction is simply to lay the 400-500 eggs, in paired strings each resembling a rosary. Preferred nesting sites are in holes in mud banks below the water-line, but protected from the main flow of the river which is prone to flush out the eggs after heavy rains. Fertilisation takes place externally, without copulation. Each globular yellow egg measuring about 6 x 4 mm floats in a clear bead-shaped gelatinous envelope, which swells to about two centimetres.

The big surprise is that males exhibit parental care, remaining and guarding the egg strings at the laying site. Oscillatory movements of the tail serve to keep the eggs well oxygenated, and the sheer presence of such a large parent must prove effective defence against the attacks of any predatory fish.

Breeding occurs during August and September, with the female laying her eggs in the male's territory, perhaps where the male has excavated a pit or burrow. The male drives the female away as soon as he has fertilised the eggs, because like all individual JGSs they are quite willing to eat anything smaller than them!

The eggs develop towards hatching over a period of 8-10 weeks. Measuring approximately three centimetres long when they hatch, the aquatic larvae have three pairs of fringed external gills, two fingers on each hand, and rear limb stumps. The larvae begin to disperse soon after hatching, in about November, but have settled in a home range by the following May.

Not until about four or five years old and 20-22 cm long (earlier in captivity by about a year) do they undergo a partial metamorphosis when the gills are absorbed, the body flattens, and the young change their behaviour, adopting a new life on the river bottom, though now with functional lungs, they must return periodically to the surface to breathe (they do so once every 6-10 minutes in captivity or in poorly oxygenated water, but the interval is considerably longer in their fast-flowing highly oxygenated mountain streams).

Adults remain in the same range for many years, even decades. Growth is slow and steady with the rate dependent on the water temperature and food availability, and much slower in the wild than in captivity. Tochimoto-san was reticent to guess how long they might live, but considers that some of his study animals are quite likely to outlive him, perhaps by several decades. Males are said to be capable of reproducing four years after hatching, and females five, but like so much factual information this traces its origin to papers published in the 1920s and before.

Japanese Giant Salamander Researcher.

Salamander research requires endless patience, and nocturnal adventures along uneven rocky-bedded rivers, but the price could be a giant!

Text and Photographs: Mark Brazil

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Mark Brazil

A writer, naturalist and wildlife guide, Mark spends half of each year travelling in search of wildlife and the other half writing about it from his base in Hokkaido.

Born and educated in England and Scotland, Mark spent more than ten years involved in the making of natural history documentaries for television, and nine years as a professor of biodiversity of conservation at Rakuno Gakuen University near Sapporo.

He began contributing his column, Wild Watch, to The Japan Times newspaper in April 1982, and has been writing about natural history and travel ever since.

His latest book, a field guide, Birds of East Asia, was published to considerable acclaim in 2009, by A&C Black and Princeton University Press.

You can learn more about Mark and his work via his website:

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