WHEN IS A CRYPTID NOT A CRYPTID? WHEN IT'S THE MEGAMOUTH SHARK…MAYBE?

Photograph of the very first megamouth shark specimen to come to the attention of scientists, or anyone else for that matter, and revealing very readily why this remarkable species received its memorable name (© Charles Okamura/Honolulu Advertiser - reproduced here by kind permission of the Honolulu Advertiser, on a strictly non-commercial Fair Use basis for educational/review purposes only)

This is my 700^th ShukerNature blog article – so to celebrate such a momentous occasion, I decided to choose for its subject something that was big – and not just in physical size either, but also in zoological significance. Needless to say, the megamouth shark Megachasma pelagios accords perfectly with both of these requirements, so here it is, making its long-awaited starring-role debut on ShukerNature.

In terms of precise cryptozoological definitions, what makes a cryptid a cryptid, i.e. a creature of cryptozoology? There are two basic criteria. Namely, that it is an animal claimed to exist by and be known to people sharing its geographical location and habitat (i.e. it is ethno-known), but which is not officially recognized or formally described by science (i.e. it is scientifically unknown). Virtually all of the 20^th and 21^st Centuries' most spectacular 'new' creatures were once cryptids, i.e. animals already known locally but hitherto unknown scientifically, such as the okapi, mountain gorilla, Komodo dragon, coelacanths, Vu Quang ox (saola), and dingiso tree kangaroo, to name but a few.

Side view of my megamouth model (© Dr Karl Shuker)

However, there is one very dramatic zoological discovery that is an equally dramatic exception to this rule – the megamouth shark. When what proved to be the first of a considerable series of procured specimens in the years and decades to follow was accidentally captured off Oahu in the Hawaiian Islands on 15 November 1976 by the anchor of a research vessel (see later for full details), its remarkable, visually unique species was entirely new not only to scientists but also to everyone else, even local fishermen. No-one anywhere had ever seen anything like it before.

In other words, this newly-revealed shark species was not just scientifically unknown, it was ethno-unknown too. That in turn means that despite erroneous claims to the contrary as present on many websites and elsewhere, according to strict cryptozoologial conventions the megamouth shark was never a cryptid. Its discovery was totally unheralded, completely unpredicted, and thoroughly anomalous.

Size comparison between the megamouth's holotype specimen and a human diver (© Slate Weasel/Wikipedia, public domain)

Although such a situation is far from unusual among very small, inconspicuous animals, with creatures as big (one Taiwanese specimen was apparently 23 ft long) and inordinately distinctive (thanks to its gargantuan mouth) as the megamouth, conversely, it was (and remains) virtually unparalleled.

In fact, the only readily comparable example that comes to mind, and which was also brought to scientific and public attention for the first time during the mid-1970s, were the 10-ft-tall or so vertical tube worms with flamboyant crimson tentacles that were discovered fringing the never-before-visited hydrothermal vents or rifts on the ocean floor by scientists inside the US research submarine Alvin. Specimens were collected, studied, and their radically new species, outwardly unlike anything ever encountered before but most closely related to the pogonophorans or beard worms, was subsequently described and formally named Riftia pachyptila.

Distribution map for the megamouth shark (© Chris_huh/Wikipedia – CC BY-SA 3.0 licence)

Back to the megamouth, and during the decades succeeding its 1970s unveiling, there have been just over 100 additional specimens recorded, including some living ones as well as beached carcases, and from almost every major oceanic region worldwide. This makes it all the more astonishing that such a sizeable, unmistakable species of shark had remained wholly undetected by humankind down through all the ages until as late in time as 1976 – because there certainly did not appear to be a single recorded instance of anyone anywhere ever having previously reported seeing or catching something that could conceivably have been a megamouth.

To me, however, this situation has always seemed to be just too incredible, too implausible, surely, to be true – as a consequence of which I have spent a lot of time through the years searching online for any clues that may indicate otherwise, i.e. that might, just might, turn up some evidence for prior (pre-1976) knowledge of the megamouth's existence, which in turn would mean that it was indeed a cryptid after all. Yet time and again, my searches were always in vain – it almost seemed as if by some unexplained biological miracle, on 15 November 1976 the megamouth had spontaneously generated from seawater! But then, one day, some information ostensibly of the kind that I had been actively seeking for so long sought me out instead.

Megamouth shark illustration (© CSIRO National Fish Collection - Dianne J. Bray, Megachasma in Fishes of Australia/Wikipedia – CC BY 3.0 licence)

On 8 December 2011, responding to a photograph of the finalized full cover for my forthcoming Encyclopaedia of New and Rediscovered Animals that I had posted on my Facebook timeline (or wall, as it was called back then), correspondent H. James Plaskett added the following short but immensely interesting comment:

The Bermudian Teddy Tucker told me the Chinese were catching the megamouth shark in the Pacific in the 1880s.

Needless to say, I found this claim to be quite electrifying in terms of its potential scientific significance, so I lost no time in contacting James and eliciting from him some contact details for Teddy Tucker, after which I emailed him with a request for any additional details that he could send me. Here, in a ShukerNature world-exclusive, is his full, never previously-published response, dated 18 January 2012:

I received your inquiry with interest.  During the Beebe Project, we, the National Geographic, University of Maryland and several organizations interested in the deep ocean, were primarily interested in the habitats of the water column.  We observed many large deep sea animals that were impossible to accurately identify.  These creatures were seen on deep water cameras deployed to 6,000 feet.

During seventy years of working on and in the ocean, mostly around Bermuda, in the fall of the year, Oct., Nov. and Dec., the Cuvier beaked whales feed around the sea mounts, situated on the Bermuda Rise.  The food these whales seemed to prefer is a large mid-water octopus, how large I do not know, never having seen one intact.  I have collected large pieces of these octopus[es] during the feeding frenzy of these whales on the surface.

During an expedition to the Pacific, I had the opportunity to witness a similar feeding frenzy by a similar type of whales feeding on what appeared to be the same sort of octopus, during this trip two Japanese scientists on board, told me that the Chinese fished for these large gelatinous type of octopus in large deep water drift nets, which occasionally caught large megamouth sharks, which tangled in the nets.

It would seem that the shark and the whale might feed on this type of octopus, at least they seem to feed in the same depth.  It would be difficult to make a positive identification without having an actual specimen.  It would be reasonable to assume that the Chinese would have known about the megamouth for many years, as they have been using deep water drift nets for a long time.

I hope this information is helpful.

Megamouth shark showing huge mouth, used for filter-feeding – preserved specimen, Japan (© OpenCage/Wikipedia – CC BY-SA 2.5 licence)

Needless to say, as a dedicated planktivorous filter-feeder, swimming slowly through the sea with its huge mouth wide open, filtering water for plankton and jellyfishes, the megamouth shark is unlikely to feed upon octopuses, gelatinous or otherwise. Conversely, at least 11 megamouth specimens have been recorded off Japan and one off mainland China since 1976 (plus others off Taiwan), so its modern-day presence in this region of the Pacific Ocean is fully confirmed. As to whether Chinese fishermen were catching specimens almost a century prior to 1976, however, this bold but fascinating claim presently remains unverified.

Yet, undeniably, any such claim also remains extremely tantalizing, and offers a worthwhile starting point from which to explore anew the exciting possibility that this most notable non-cryptid may turn out to have been a bona fide cryptid after all. Having said that, my periodic peregrinations online in search of megamouth knowledge among bygone Sinian fishing folk and fishing communities has yet to prove successful – but there is always tomorrow... Or even yesterday:

Californian newspaper report from 1966 concerning an unidentified shark that may have been a megamouth? (© Times, San Mateo - reproduced here on a strictly non-commercial Fair Use basis for educational/review purposes only)

Also of potential interest here is the above Californian newspaper report from 15 August 1966, which came to my attention in June 2016, courtesy of fellow British cryptozoological researcher Richard Muirhead. It appeared in The Times (San Mateo).

In view of the fact that several megamouth shark specimens have been washed ashore off California or recorded in Californian waters (see later), I wonder if the extremely big unidentified shark seen and photographed underwater off Los Angeles in that 1966 newspaper report was a megamouth. If so, this scientifically-documented specimen had been recorded 10 years before the megamouth's official scientific discovery in 1976. Alternatively, perhaps it was a Pacific sleeper shark Somniosus pacificus, due to the great depth at which it was sighted, but this species was already well known to ichthyologists well before 1966 (it was formally named in 1944).

The Encyclopaedia of New and Rediscovered Animals (© Dr Karl Shuker/Coachwhip Publications)

Meanwhile, for anyone who has not previously encountered the engrossing history of the megamouth's modern-day discovery, here is how I documented it in my Encyclopaedia of New and Rediscovered Animals, published in 2012:

Most fishermen have a cherished tale or two about 'the big one that got away', but none can surely compete with the following version - in which, just for a change, the whopper in question did not get away, much to the delight of marine biologists throughout the world.

            On 15 November 1976, a team of researchers from the Hawaii Laboratory of the Naval Undersea Center (now known as the Naval Ocean Systems Center) was aboard the research vessel AFB-14, sited about 26 miles northeast of Kahuku Point, Oahu, in the Hawaiian Islands. During the course of their work, two large parachutes employed as sea anchors were dropped overboard, and lowered to a depth of 500 ft. Later that day, when the boat was ready to leave for home, the researchers hauled the parachutes back up - and found that one of them had drawn up the greatest ichthyological discovery since the coelacanth! Entangled in the parachute was a gigantic shark, measuring 14.5 ft in total length, weighing 1653 lb, and differing radically in appearance from all other sharks on record.

            Recognising its worth, the team hauled its mighty body aboard on rollers, and sent it at once to the Naval Undersea Center's Kaneohe Laboratory, where biologist Lieut. Linda Hubbell lost no time in contacting the University of Hawaii. Next morning, it was examined by Dr Leighton R. Taylor, director of the university's Waikiki Aquarium, after which its body was quick-frozen at a firm of tuna packers, and retained there until, on 29 November, it was transported (still frozen) to a specially-constructed preservation tank at the National Maritime Fisheries Service's Kewalo dock site. It was then thawed and injected with formalin, procedures that marked the commencement of what was to be an intensive period of study in relation to this unique specimen - swiftly recognised to represent a dramatically new species never before brought to the attention of science. The study lasted almost seven years, and was undertaken jointly by Dr Taylor, Dr Paul Struhsaker of the Fisheries Service, and shark specialist Dr Leonard Compagno from San Francisco State University. Preserved, the specimen is now held at Honolulu's Bernice P. Bishop Museum.

            The head of this strange shark was very large, long, and broad, but not pointed like that of more typical sharks, whereas its lengthy, cylindrical body tapered markedly from the broad neck to the slender heterocercal tail (i.e. the tail's upper lobe was much longer than its lower lobe). Its pectoral fins were also long and slender, but its pelvic fins and anal fin were very small - smaller than the first of its two dorsal fins. Identifying it straight away as a male, its pelvic fins bore a pair of elongate claspers (a male shark's copulatory organs).

Dorsolateral view of my megamouth model, showing its huge head and jaws (© Dr Karl Shuker)

            The specimen's huge size made its species, on average, the sixth largest species of modern-day shark known to science, but even more striking than its overall bulk was its mouth. Relative to the rest of its body, its mouth was exceedingly large and wide - a feature that soon earned it in newspaper reports a very fitting soubriquet - 'megamouth', which became accepted by science as this species' official English name. In addition to its size, the megamouth's mighty orifice was distinguished by its thick lips, more than 400 tiny teeth arranged in 236 rows, a very unusual anatomy which meant that its jaws did not lower at the bottom like those of most sharks but flapped open at the top instead, and - most startling of all - a silvery mouth lining that glowed in the dark!

            Despite initial speculation that this unexpected last-mentioned feature was due to light-emitting structures comparable to the bioluminescent organs of many deepsea fishes and other benthic life, insufficient evidence was obtained from the study to verify this. Even so, when taken together with the megamouth's immense size but only tiny, relatively useless teeth, various other anatomical attributes, plus the great depth at which it was captured, its glowing jaws indicated that this mysterious marine form was itself a deepsea denizen, whose lifestyle probably consisted of slow cruises through the inky darkness of the sea's depths with its huge, glowing jaws held open, to entice inside great numbers of tiny marine organisms. Thus, the megamouth was a harmless plankton feeder, a gentle giant.

            All of this and much more was recorded in the paper prepared by Taylor, Struhsaker, and Compagno, constituting the megamouth's formal scientific description and published on 6 July 1983. Their study had revealed this mighty creature to be so unlike all other sharks that they had not merely classed it as a new species, they had also placed it in an entire genus and family all to itself. Approving of 'megamouth' as its common name, Taylor and colleagues made it the basis of this species' scientific name too, christening it Megachasma pelagios ('great yawning mouth of the open sea') - sole member of the family Megachasmidae, but most closely allied to the basking shark Cetorhinus maximus, another plankton feeder.

            Attempts to catch a second megamouth for comparison purposes proved unsuccessful until November 1984, when another megamouth was caught - but, once again, completely by accident. This time, a commercial fishing vessel named Helga took the honours, snaring it unknowingly within a gill net at a depth of only 125 ft, while based close to California's Santa Catalina Island, near Los Angeles. Needless to say, this priceless specimen was carefully brought ashore, and was sent at once to the Los Angeles County Museum of Natural History. Tissue samples were taken and stomach contents removed, after which its 14-ft-long body was stored in a frozen state within a temporary case until work upon a specially-prepared fibreglass display unit was completed, whereupon the new megamouth was preserved and retained thereafter within its 500 gallons of 70 per cent ethanol.

Preserved megamouth in tank at the Western Australian Maritime Museum (© Saberwyn/Wikipedia – CC BY-SA 3.0 licence)

            The megamouth's known distribution range expanded dramatically with the third specimen's discovery. On 18 August 1988, an adult male almost 17 ft long was found washed up on a beach near Mandurah, a holiday resort south of Perth, Western Australia. When news of its appearance reached the Western Australian Museum, ichthyologist Dr Tim Berra (visiting from Ohio State University) and a team of fish researchers swiftly travelled to the beach to salvage the shark's body. This was just as well, because some of the resort's residents, not realising its immense scientific significance, had been attempting (albeit unsuccessfully) to push it back into the sea!

            The scientists were delighted to find that this latest megamouth was still in good condition, and it was ultimately preserved and housed in a fibreglass display tank like that of the Los Angeles specimen. During the tank's construction, it was retained in a frozen state, enabling the museum's taxidermist to prepare a plaster cast of its body for exhibition.

            On 23 January 1989, a fourth megamouth appeared, stranded dead on the sandy beach of Hamamatsu City in Japan's Shizuoka Prefecture, yielding the first record of this species from the western Pacific. An adult male, estimated at over 13 ft in total length, it attracted the notice of a photographer who took some good pictures of it that demonstrated beyond any doubt that it really was a megamouth - all of which was very fortunate, because shortly afterwards, before there was time to rescue it, this scientifically invaluable specimen was washed back out to sea and lost. The photos, however, were sent to Dr Kazuhiro Nakaya, who published them in a short Japanese Journal of Ichthyology report. Less than six months after this specimen's brief appearance, a second Japanese megamouth made the headlines, when on 12 June a living specimen was caught in a net in Suruga Bay. Photographs confirming its identity as a megamouth were taken, after which it was released unharmed.

Megamouth shark, preserved, Japan (© OpenCage/Wikipedia – CC BY-SA 2.5 licence)

The next episode in the megamouth saga however, was truly spectacular. On 21 October 1990, a sixth specimen turned up, measuring 16 ft 3 in and snared in a drift net off Dana Point, in California. It was towed to shore by the net's vessel, and was found to be still alive. Marine biologist Dr Dennis Kelly, from the Orange Coast College, gently examined the huge fish, and decided that although it would not survive in captivity, it would probably live if released back into the sea. And so, very carefully, it was set free, and was filmed underwater as it swam slowly down into the depths from which it had earlier arisen.

Moreover, capitalising upon this unique opportunity to discover a little more about its species' lifestyle, a radio transmitter was attached to its body. This enabled researchers to track it in the sea for the next three days (after which time the transmitter's batteries ran out), and revealed that it exhibited vertical migration - moving to the ocean surface only at night, and descending back into the depths at dawn - which explains how this extremely large and striking species had escaped scientific detection for so long.

A living megamouth (© FLMNH Ichthyology/Wikipedia – CC BY-SA 4.0 licence)

            Almost exactly 18 years after the first one was hauled up by a research vessel off Oahu, a seventh megamouth appeared. This proved to be the first female specimen on record, and was washed up in Hakata Bay, Kyushu, on 29 November 1994. The third Japanese megamouth, its body measured 15.5 ft, weighed 0.8 ton, and was transported to Fukuoka's Marine World Museum, where it was deep-frozen, prior to permanent preservation.

            A hitherto unsuspected portion of this species' distribution range was revealed on 4 May 1995, when the first megamouth to be recorded from the Atlantic Ocean was captured by a French tuna fishing vessel, Le Bougainville, in its purse seine, roughly 40 miles off Dakar, Senegal. This eighth megamouth was a young male, measuring only 6 ft or so in total length. Regrettably, however, its body was not preserved.

            Megamouth #9 extended its species' known distribution even further, for this specimen, another young male, approximately 6 ft 3 in long, was procured off southern Brazil, on 18 September 1995. Its body was retained by the Instituto de Pesca, in São Paulo, Brazil.

            It was the fourth time for Japan when the megamouth made its next confirmed appearance, courtesy of only the second known female specimen turning up on 1 May 1997 near Toba. More than 16 ft long, its carcase was taken to Toba Aquarium.

Megamouth shark preserved at Toba Aquarium, Japan (© OpenCage/Wikipedia – CC BY-SA 2.5 licence)

            On the evening of 20 February 1998, yet another specimen (#11) of this maritime megastar surfaced - caught by three Filipino fishermen in Macajalar Bay, Cagayan de Oro, in the Philippines, and estimated to measure around 16 ft. The first on record from this island group, its taxonomic identity was confirmed on 21 March 1998 by Dr Leonard Compagno. Unfortunately, its body was hacked to pieces after it had been landed and photographed. Moreover, a female megamouth captured at Atawa in Mie, Japan, on 23 April 1998 was subsequently discarded.

            Megamouth #14, another female specimen and measuring approximately 17 ft long, was captured in a drift gillnet roughly 30 miles west of San Diego, California, on 1 October 1999. The third megamouth to be caught off southern California, after being photographed it was released again, still in good health.

            In addition, Genoa Aquarium worker Pietro Pecchioni claimed in an internet shark discussion group that he saw and photographed what may have been a living megamouth, being harassed by three sperm whales near the island of Nain, off northern Sulawesi, Indonesia, on 30 August 1998. The shark measured 15-18 ft long, and Pecchioni spied it while in the company of a group of people participating in a WWF whale-watching programme. When the whales saw the watchers, they came towards them, then swam away, so the shark survived. At the time of his claim (4 September 1998), Pecchioni's photos had not been developed, but when they were, the shark’s identity as a megamouth was confirmed (making it megamouth specimen #13); and the encounter was formally documented by Pecchioni and Milan University zoologist Dr Carla Benoldi in 1999 on the website of the Florida Museum of Natural History’s ichthyology department.

Megamouth specimen preserved at Keikyu Aburatsubo Marine Park, Kanagawa, Japan (© Oos/Wikipedia – CC BY-SA 3.0 licence)

On 19 October 2001, megamouth #15, a male specimen roughly 18 ft long, was caught alive in a drift gillnet by a commercial swordfish vessel sited about 42 miles northwest of San Diego. After a United States National Marine Fisheries Service observer aboard the vessel had photographed its unexpected catch and had also taken a tissue biopsy from it, this megamouth was also released in good condition.

Another notable specimen was megamouth #23, which was washed up on 13 March 2004, onto Gapang Beach in northernmost Sumatra. Only relatively small, measuring just over 3 ft in length, it was subsequently frozen at the Lumba Lumba Dive Centre, and following formal examination by scientists it was deposited at Cibinong Museum. Interestingly, because of marked differences in shape between this megamouth’s dorsal fins and those of all previously recorded specimens (and also between its anal fin and those of previous specimens), when formally documenting it later that year a team of researchers suggested that these differences may indicate the existence of a second species of megamouth, but no further evidence for such a situation has been presented since then.

Megamouth #26 was discovered on 4 November 2004, stranded but still alive at Namocon Beach, in Tigbauan, Iloilo City, in the Philippines. An adult female measuring approximately 16.5 ft long and weighing roughly a ton, this was the third megamouth to have been recorded in the Philippines, and bore a wound that may have been a spear wound, or possibly a bite from the cookie cutter shark Isistius brasiliensis. The megamouth was formally identified the day after its discovery by an official from the Southeast Asia Fisheries Development Center (SEAFDEC), after which 16 men carried it to a SEAFDEC aquarium where it lived for a day. It was then preserved in 10 per cent formalin within a 1-ton fibreglass tank.

Megamouth sightings map, 1976-2010 (© Skyler30/Wikipedia – CC BY-SA 3.0 licence)

            As of August 2011, 53 specimens of the megamouth shark have been obtained or conclusively sighted [but as of August 2020 this number has increased to just over 100]. The three most recent ones are: #51, a specimen of unknown sex caught off eastern Taiwan on 19 June 2010, but later cut up for meat that was sold at a local market, with only a jaw retained; #52, a dead juvenile male specimen captured by fishermen close to the western Baja California peninsula of Mexico on 12 June 2011; and #53, an individual of unspecified sex but measuring approximately 10 ft long that was recorded from Japan’s Kanagawa Prefecture on 1 July 2011. A comprehensive listing of these, together with pertinent details of their respective discoveries, plus a detailed bibliography of sources, can be accessed on a number of online websites.

            Finally: an intriguing footnote (fin-note?) to the megamouth history is that this species' own discovery set the scene for a remarkable parasitological parallel. During the study of the very first megamouth specimen, an extremely strange form of tapeworm was found inside its intestine. When closely examined, this peculiar parasite proved to be not just a new species (later named Mixodigma leptaleum), but one so different from all others that it required a completely new genus and family - exactly like its megamouth host!

Since I wrote that account, fossilised teeth from what are believed by some palaeontologists to have been two ancestral megamouth species (M. alisonae and M. applegatei) dating back to the late Eocene/early Miocene have been described. If correctly identified, these readily prove – if proof were needed! – that the present-day megamouth species M. pelagios did not generate spontaneously in 1976 after all!

On the contrary, this amazing creature's existence and evolution can be traced back millions of years – making it even more astonishing, vertical migration notwithstanding, that it successfully eluded discovery by science and the public alike until less than half a century ago (unless there really are some Sinian insinuations to the contrary still to be uncovered?).

Miniature Sheet depicting the megamouth, issued by the Comoros in 2010, from my own stamp collection (© Comoros Philatelic Bureau – reproduced here on a strictly non-commercial Fair Use basis for educational/review purposes only)

In view of this, I can't think of a better way in which to bring ShukerNature's mega-monograph of the megamouth to a fitting close than by reflecting upon the following quote from the previously-mentioned ichthyological expert Dr Leighton R. Taylor, as contained in a published interview with the Waikiki Beach Press newspaper:

The discovery of megamouth does one thing. It reaffirms science's suspicion that there are still all kinds of things - very large things - living in our oceans that we still don't know about. And that's very exciting.

It is indeed!

 

UPDATE, 10 May 2023 - I've learned today from crypto-colleague Tyler Greenfield that the 1966 mystery shark was subsequently confirmed to be a sleeper shark (family Somniosidae). Photographs of it, taken by John Isaacs/Scripps Institute, were published in the 1971 book The Face of the Deep, authored by Bruce C. Heezen and Charles D. Hollister. Thanks Tyler!

PS – If you would like to see footage of a living megamouth shark, be sure to click here to see one that was filmed off Japan earlier this year, 2020; plus here and here to see others as featured in a couple of online mini-megamouth documentaries.

Present but uncredited on several websites online - how a genuine photograph of a beached megamouth shark has been converted by hoaxer(s) unknown into a fake photograph of a beached plesiosaur (© owner/s unknown to me, reproduced here on a strictly non-commercial Fair Use basis for educational/review purposes only)

THE SIX-LEGGED SEA SERPENT OF STRONSAY - STILL BASKING IN CRYPTOZOOLOGICAL CONTROVERSY?

Modern-day artistic representation of what the Stronsay beast might have looked like if it had literally resembled in life the eyewitness descriptions of it in death (© Tim Morris)

Down through the centuries, countless reports of mysterious sea ‘monsters’ have been reported, often grouped together within that infamously heterogeneous cryptozoological conglomerate popularly known collectively as the Great Sea Serpent. In most cases, such reports consist entirely of eyewitness sightings, unsubstantiated by anything tangible that can be directly examined afterwards by interested researchers. Occasionally, however, physical evidence IS obtained…

Perhaps the most famous of such cases occurred at Stronsay, one of the Orkney Islands off northern Scotland. On 26 September 1808, farmer John Peace was fishing east of Rothiesholm Point when he saw what seemed to be the carcase of a whale, cast up onto the rocks, above which were flocks of circling seabirds. He rowed up to it in his boat and examined it, and found that it was a very peculiar-looking creature, which did not resemble anything known to him. At that same time, another farmer, George Sherar, was watching Peace from the shore, and was able to confirm all of this. About 10 days later, moreover, he was able to see it for himself, because it was washed ashore on Stronsay, lying on its belly just below the high tide mark.

When Sherar discovered it there, he measured it, and found it to be 55 ft long. At least two other eyewitnesses (the afore-mentioned Peace and carpenter Thomas Fotheringhame) also measured it, and they obtained the same result. It was very serpentine, almost eel-like in general build, but possessed a 15-ft neck, a small head, and a long mane running along its back to the end of its tail. Most bizarre of all, however, was that it seemed to have three pairs of legs, and each foot had five or six toes. Sherar salvaged some vertebrae and the skull of this extraordinary creature – duly dubbed the Stronsay beast.

From the Wernerian Natural History Society's memoirs for 1808-1810, published in 1811, a sketch of the Stronsay sea serpent based upon eyewitness George Sherar's description and agreed by Sherar to be "an exact resemblance" of what he saw (public domain)

Details of its discovery and description ultimately reached Patrick Neill, secretary of Edinburgh's Wernerian Natural History Society, and at a meeting of the society on 19 November 1808 Neill released some details on this subject. At the next meeting, on 14 January 1809, he gave the Stronsay beast a formal scientific name - Halsydrus pontoppidani *, 'Pontoppidan's water snake of the sea' (after Erik Pontoppidan, an 18^th-Century Norwegian bishop who had collected many sea serpent reports).

Erik Pontoppidan (public domain)

At that same meeting, Scottish anatomist Dr John Barclay, who had examined some of the beast's remains in Orkney, presented a paper in which he described the vertebrae, skull, and one of the creature's legs. His paper, accompanied with detailed diagrams, was published in 1811, within the society's memoirs, and attracted a great deal of attention. The vertebrae were very striking, resembling cotton reels, and were cartilaginous, but with calcification that radiated from the centre of each vertebra in a star-like pattern. The leg was also cartilaginous, but was not a real, jointed leg at all; it was merely a fin.

Dr John Barclay, 1820 portrait (public domain)

To many people, these features meant little, but they meant a great deal to the eminent naturalist Sir Everard Home, who was working at that time upon an exhaustive study of the basking shark Cetorhinus maximus - the world's second largest species of shark, but generally harmless, living on plankton. When Home heard about the Stronsay beast, he felt sure that it must have been a shark. This is because the only creatures to have cartilaginous vertebrae are sharks and rays, and the only creatures to have cartilaginous vertebrae with star-shaped calcification are sharks. Furthermore, when he compared the Stronsay beast's vertebrae, skull, and other salvaged remains with the corresponding portions of a known specimen of basking shark, they matched very closely.

Sir Everard Home (public domain)

Yet the long-necked, six-legged, mane-bearing Stronsay beast looked nothing like a basking shark - so how could this drastic difference in appearance be resolved? In fact, it was quite simple.

Stronsay beast vertebrae, an engraving from Barclay's 1811 paper (public domain)

When basking shark carcases begin to decompose, the entire gill apparatus falls away, taking with it the shark's characteristic jaws, and leaving behind only its small cranium and its exposed backbone, which have the appearance of a small head and a long neck. The triangular dorsal fin also rots away, sometimes leaving behind the rays, which can look a little like a mane - especially when the fish's skin also decays, allowing the underlying muscle fibres and connective tissue to break up into hair-like growth.

Additionally, the end of the backbone only runs into the top fluke of the tail, which means that during decomposition the lower tail fluke falls off, leaving behind what looks like a long slender tail. The pectoral and sometimes the pelvic fins remain attached, but become distorted, so that they can (with a little imagination!) look like legs with feet and toes. The resulting deceptively plesiosaur-like carcase is popularly (and fittingly) dubbed a pseudo-plesiosaur.

Finally, male sharks have a pair of leg-like copulatory organs called claspers, which would yield a third pair of 'legs', as happened with the Stronsay beast. Suddenly, a male basking shark has become a hairy six-legged long-necked sea serpent!

How a basking shark carcase decomposes into a pseudo-plesiosaur (© Markus Bühler/Journal of Cryptozoology)

Over the years, almost all of the Stronsay beast's preserved remains have been lost or destroyed, but three vertebrae are retained in Edinburgh's Royal Museum of Scotland - the last remnants of Stronsay's world-famous hexapodal sea serpent. Its mystery, conversely, continues to the present day, and for very good reason. The longest conclusively-identified basking shark that has been accurately measured was a truly exceptional specimen caught in 1851 in Canada's Bay of Fundy; whereas the average length for its species is under 26 ft, this veritable monster was a mighty 40 ft 3 in. Yet even that is almost 15 ft less than the length claimed by eyewitnesses for the Stronsay beast. Even the largest scientifically-measured specimen of the world's biggest fish - the whale shark Rhincodon typus - was only(!) 41.5 ft long.

Accordingly, in 2008 archaeogeneticist Dr Yvonne Simpson, who had been studying the Stronsay beast's few preserved remains since 2001, was reported in various media interviews as stating that due to its size she wondered whether it may have been some other species of shark rather than a basking shark, and was hoping to conduct DNA tests upon some newly-recovered bone fragments from this contentious carcase that had been given to her by a private collector (Daily Telegraph, 8 September 2008). However, nothing further seems to have emerged regarding this potentially exciting prospect.

Some cryptozoologists have also questioned whether the 55-ft Stronsay beast really was a basking shark, speculating that it may have belonged to a still-unknown, giant relative. One of the world's largest known sharks, the formidable megamouth Megachasma pelagios, remained wholly unknown to humankind until 15 November 1976, when the first recorded specimen was accidentally hauled up from the sea near the Hawaiian island of Oahu. Consequently, the prospect of undiscovered species of extra-large shark still eluding scientific discovery in modern times is far from being as unlikely as one might otherwise assume.

Megamouth shark (© FLMNH Ichthyology/Wikipedia - CC BY-SA 4.0 licence)

Alternatively, might the Stronsay beast simply have been an exceptionally large specimen of basking shark after all? In a Facebook comment concerning this classic sea monster carcase posted on 16 October 2019, American cryptozoologist Ken Gerhard offered the following pertinent thoughts:

Of course there were more outsized fish in those days - before population explosions, pollution and aggressive, industrialized fishing took hold. Perhaps the Stronsay Beast represented one of the last monster-sized basking sharks? 

This is the possibility that I personally consider most reasonable.

A third option is that the latter beast's size may have been measured inaccurately by its eyewitnesses – the option favoured by Home, who discounted the claimed 55-ft total length in favour of a more conservative yet still very impressive 36 ft. Yet if so, it seems very strange that three separate people measured it (one of whom, Thomas Fotheringhame, was a carpenter and therefore skilled in accurate measurement) and all obtained the same 55-ft total length for it. As is so often true with cryptozoological cases that date back quite considerably, it is likely that no conclusive answer will ever be obtained, so the controversy surrounding the Stronsay beast seems destined to persist indefinitely.

Having said that: during December 1941, history somewhat repeated itself in the Orkneys when a strange carcase, 25 ft long, was washed ashore at Scapa Flow. Its superficially prehistoric, plesiosaurian appearance was presumably sufficient for Provost J.G. Marwick, who had documented it in detail in a local newspaper account (Orkney Blast, 30 January 1942), to dub this enigma 'Scapasaurus'. Fortunately, a single vertebra from its remains was preserved and retained at London's Natural History Museum, which readily identified it as a basking shark.

* Taxonomic tail-note: Halsydrus pontoppidani Neill, 1809 is currently designated as a junior synonym of the basking shark's officially-recognised binomial name, Cetorhinus maximus Gunnerus, 1765.

Basking shark (public domain)