NEW ZEALAND'S KAWEKAWEAU AND DELCOURT'S UNIQUE MEGA-GECKO - THE REMARKABLE HISTORY OF AN ONGOING HERPETOLOGICAL MYSTERY

Are Delcourt's giant gecko and New Zealand's mythical kawekaweau one and the same? (© Markus Bühler)

The largest species of gecko known to exist today in New Zealand is Duvaucel's gecko Hoplodactylus duvaucelii, which attains a total length (snout-tip to tail-tip) of up to 12 in.

Just over a century ago, however, a much more sizeable species may have still survived here - if the evidence presented by a unique and truly extraordinary taxiderm specimen is anything to go by – and may even still do so today. I documented this fascinating case within my book The Encyclopaedia of New and Rediscovered Animals (2012) as follows:

Duvaucel's gecko Hoplodactylus duvaucelii (© Jennifer Moore/Wikipedia - CC BY 3.0 licence)

The history of this mysterious taxiderm mega-lizard began sometime between 1833 and 1869, because that was the period during which France's Marseilles Natural History Museum had received a specimen of a very unusual lizard from an unrecorded locality. As a mounted taxiderm exhibit, it was subsequently put on open display at the museum - where, for many years, it remained in full view of countless numbers of visitors, not to mention generations of museum scientists and many others who passed through from elsewhere. Yet, unbelievably, never once in all that time did anyone realise, or even suspect, that it belonged to a dramatically new species - one that had never been recorded by science!

The decades rolled by, but still the ignored lizard's true identity remained undisclosed and uninvestigated - until as recently as 1979, when this strange specimen attracted the curiosity of the museum's herpetology curator, Alain Delcourt. Eager to learn more about it, Delcourt took some photographs, and along with the specimen's measurements he sent them for identification to a number of reptile experts around the world.

New Caledonian giant forest gecko Rhacodactylus leachianus (© Alfeus Liman/Wikipedia – free use permitted with copyright holder attribution)

They ultimately reached Canadian biologist Dr Anthony P. Russell, who in turn showed them to Villanova University herpetologist Dr Aaron M. Bauer. Russell and Bauer recognised that the specimen was clearly a gecko, but of grotesquely gigantic proportions, measuring fractionally over 2 ft in total length. (This is 54 per cent larger than the world's next biggest species of modern-day gecko, the New Caledonian giant forest gecko Rhacodactylus leachianus.) It was a short-headed, bulky-bodied creature, with sturdy legs and a long pointed tail, and was handsomely marked along its back with dark reddish-brown, longitudinal stripes overlying its yellowish-brown background colouration. In overall appearance, it compared fairly closely with geckos of the genus Hoplodactylus - except, once again, for its huge size.

The existence of this enigmatic lizard finally became known to the world at large in 1984, when Bauer's investigations of its possible origin led him to New Zealand. And in 1986 its species was formally described by Bauer and Russell, who named it Hoplodactylus delcourti - in recognition of Delcourt's laudable action in rescuing this long-neglected form from more than a century's worth of zoological obscurity.

Delcourt's giant gecko, the only known specimen, viewed ventally (left) and dorsally (right) (© International Society of Cryptozoology and Dr Aaron Bauer – reproduced here on a strictly educational, non-commercial Fair Use basis only)

Its identification as a Hoplodactylus species had provided an important indication to its likely origin, because this genus's species are mostly limited to New Zealand, thus implying very strongly that this was also the home of the giant H. delcourti. Extra support for this conclusion came from Bauer's investigations here, because he learnt that Maori legends spoke of a strange New Zealand creature called the kawekaweau or kaweau. No-one had previously succeeded in identifying this mysterious animal with any known species inhabiting New Zealand, but various reports from the 19th Century described alleged encounters with such creatures.

One of the most detailed of these accounts, documented in 1873 by W. Mair, reported the killing of a kawekaweau three years earlier in North Island's Waimana Valley by a Urewera Maori chief. He had informed Mair that it was a large forest-dwelling lizard about 2 ft long, as thick as a man's wrist, and brown in colour with red longitudinal stripes. This description is a near-perfect match with that of Delcourt's giant gecko.

Dorsal view of the model of Delcourt's giant gecko featuring in the exhibition 'The Dear Departed' that was presented in 2000 by Lille Natural History Museum (© Lamiot-Wikipedia - CC BY-SA 4.0 licence)

Bauer and Russell thus believe that the kawekaweau and H. delcourti may indeed be one and the same. Sadly, however, there seems little hope that this can ever be conclusively tested, because it is almost certain that H. delcourti has been extinct for many years. How ironic, that a species as striking as this one should vanish into oblivion while a specimen was actually on public display for many years at a renowned natural history museum.

Or has it really vanished? Wellington's Dominion newspaper reported on 11 September 1984 that Wellington resident Dave Smith allegedly saw one on the western portion of North Island in the 1960s! Also, following a New Zealand radio programme broadcast on 23 March 1990 in which this species' remarkable history was recounted by James Mack, assistant curator of New Zealand's National Museum, the museum was contacted by several people who claimed to have spied living specimens of H. delcourti in recent times. The eyewitness accounts included three independent, reliable sightings all made at the same locality near Gisborne, on North Island's eastern coast.

Drawing of a kawekaweau eating a weta (© Hodari Nundu)

These, and various other reports, were followed up by herpetologist Anthony Whittaker and government scientist Bruce Thomas, but without success. Nevertheless, Whittaker believes that this species might still survive in the remote East Cape Forests. Perhaps, after all, there will come a time when Delcourt's giant gecko will be known from more than just a single, long-forgotten taxiderm exhibit.

And that is where I concluded my coverage of this enigmatic species and specimen within my book on new and rediscovered animals; but during the years since then, I have uncovered some very intriguing additional, relevant information, so here it is.

Tuatara (public domain)

The kawekaweau is not the only extra-large mystery lizard on record from New Zealand. Most famous are the taniwha – New Zealand's very own dragons. Looking somewhat like gigantic gecko lizards, or even colossal tuataras Sphenodon punctatus (those primitive superficially lizard-like reptiles endemic to New Zealand but belonging to an otherwise exclusively prehistoric reptilian lineage known as the rhynchocephalians), and bearing a row of long sharp spines along the centre of their back, taniwha are still seriously believed in even today by the Maori people, and are said to have formidable supernatural powers.

In 2002, a major highway in New Zealand had to be rerouted because of Maori claims that it would otherwise intrude upon the abode of a taniwha. Even more recently, in 2012, a similar objection arose in relation to the planned $2.6 billion construction of a tunnel in Auckland, with protestors claiming that this would disturb a taniwha that lived under the city.

Taniwha carving (public domain)

Auckland notwithstanding, these formidable creatures normally inhabited dark, secluded localities on land, as well as in large freshwater pools, and sometimes in the sea too, and were reputedly able to tunnel directly through the earth, often causing floods or landslides as a result. Each taniwha was allied to a specific Maori tribe that it protected as long as it received a fitting level of respect and veneration, but it would often attack and devour members of other tribes.

Also present in Maori traditions are the ngarara – giant lizard-like land dragons seemingly resembling monitor lizards (even though these are not known to be native to New Zealand). Various ngarara could assume the form of a beautiful young woman (as could some taniwha).

Ngarara portrayed upon a postage stamp issued by New Zealand in 2000 (© New Zealand postal services, reproduced here on a strictly educational, non-commercial Fair Use basis only)

Yet another giant mystery lizard of New Zealand is the kumi. Although occurring chiefly in Maori folklore, a real-life example was reportedly encountered near Gisborne in 1898 by a Maori bushman. He claimed that it was around 4.5 ft long, and that it clambered up into a rata tree, leaving behind some footprints on the ground, which were apparently seen by other observers too.

Could it be that in distant ages, giant lizards really did exist here, a land famous for its absence of terrestrial carnivores prior to humankind's introduction of rats, cats, and dogs? Certainly there was a vacant ecological niche for such an animal form, but without physical evidence of any erstwhile presence, such as preserved or skeletal remains, this intriguing line of speculation must remain exactly that – speculation.

Front view of the model of Delcourt's giant gecko featuring in the exhibition 'The Dear Departed' that was presented in 2000 by Lille Natural History Museum (© Lamiot-Wikipedia - CC BY-SA 4.0 licence)

All of which brings us back very appositely to Delcourt's giant gecko, because, very remarkably, there is actually no – or next to no – tangible evidence to confirm that it ever did (let alone still does) exist in New Zealand. Indeed, this anomalous paucity of physical remains for H. delcourti here is such that certain researchers have aired the view that perhaps the zoological world has been wrong all along, that in reality the provenance of the enigmatic taxiderm specimen residing at Marseilles Natural History Museum that is the only known representative of this very notable species was not New Zealand at all, but somewhere else entirely.

The leading researcher proffering this thought-provoking scenario is Dr Trevor H. Worthy, who has written and co-authored several scientific papers and other works relating to the lizards of New Zealand, past and present. In The Lost World of the Moa: Prehistoric Life of New Zealand (2002), co-authored with Dr Richard Holdaway, he noted that the taxiderm specimen of H. delcourti has been provenanced to New Zealand only upon the basis that the genus to which it belongs, Hoplodactylus, is known only from New Zealand, pointing out that not a single fossilised bone confirmed as being from this species has ever been discovered in the huge collections of palaeontological material obtained from South and North Islands (and despite much of this material dating from the late Pleistocene-Holocene time period).

Discovery and description of H. delcourti as documented in the now-defunct International Society of Cryptozoology's spring 1988 ISC Newsletter (© ISC/reproduction courtesy of J. Richard Greenwell)

True, two fossil items have been uncovered that were tentatively referred to H. delcourti by Bauer and Russell when they formally described and named this species in 1986, but Worthy is by no means convinced that such referrals were justified.

One of these items, found among a collection of tuatara remains, was a lower jaw comparable in size to that of tuataras but possessing spaces for teeth to be attached in sockets (the pleurodont condition, as found in lizards but not in tuataras). This had been obtained from Earnscleugh Cave in central Otago, South Island, during the 1800s, and was mentioned in passing within a paper authored by Captain F.W. Hutton that appeared in vol. 7 of the Transactions of the New Zealand Institute in 1874 (not 1875, as often erroneously claimed). Hutton speculated in a later, 1898 paper (see below) that it "may, provisionally, be supposed to belong to the extinct kumi, or ngarara, of the Maoris". Based upon Hutton's brief verbal description of its morphology and size (the former excluding the tuatara from consideration as noted above, yet the latter exceeding that of any lizard species known to exist in New Zealand today), Bauer and Russell deemed it possible that this potentially significant item was from a specimen of H. delcourti, but regrettably it has apparently since been lost, because according to Worthy it does not seem to be present in the collections of Otago or Canterbury Museums where the fossils procured from this cave are preserved. Consequently, it cannot be re-examined today.

Side view of the model of Delcourt's giant gecko featuring in the exhibition 'The Dear Departed' that was presented in 2000 by Lille Natural History Museum (© Lamiot-Wikipedia - CC BY-SA 4.0 licence)

Happily, however, the second item, also uncovered in Earnscleugh Cave and documented in vol. 31 of the Transactions of the New Zealand Institute by Hutton in 1898 (not 1899, as often erroneously claimed), does still survive, and is housed in Canterbury Museum. It consists of a small (0.55-in-long) rib-like bone that Hutton referred to as "a supposed rib of the kumi, or ngarara". Bauer and Russell interpreted it as the cloacal bone of a gecko (but without physically examining it); if so, this would make it large enough to be consistent with H. delcourti as the species from which it originated. Conversely, Worthy does not believe that other taxonomic identities for it can be eliminated from consideration, stating:

The bone is not referable to any class of vertebrates with certainty; it could be one of the several vestigial bones in a rat, duck, or tuatara, and considering that thousands of bones have been obtained from the site (Earnscleugh Cave) from these animals, but not a single other gecko bone, its referral to H. delcourti is most unlikely to be correct.

Head of the model of Delcourt's giant gecko featuring in the exhibition 'The Dear Departed' that was presented in 2000 by Lille Natural History Museum (© Lamiot-Wikipedia - CC BY-SA 4.0 licence)

More recently, in the multi-contributor volume New Zealand Lizards (2016), edited by Dr David G. Chapple, Worthy contributed a chapter entitled 'A Review of the Fossil Record of New Zealand Lizards', in which he again examined and discussed the stark absence of verified H. delcourti material, summarising this perplexing situation very succinctly as follows:

…there are now many thousands of fossil bones sampling palaeofaunas of all regions of New Zealand, including sites accumulated by predation by owls, falcons and other raptors, by pitfall into caves and which accumulated in sand dunes, swamps or lakes. The remains of many herpetofaunal species have been recovered from these sites in virtually all areas of New Zealand. Bones of tuatara are abundant and widespread. Not one bone of a gecko similar in size to a tuatara, as would be those of H. delcourti, has been found. But bones of a gecko the size of H. duvaucelii, New Zealand's largest extant gecko species, and of giant skinks, some much larger than any extant species, arc widespread. Therefore, if H. delcourti did derive from New Zealand, it must have existed in very localised habitats that have not yet been explored by palaeontologists. More likely, it was not a New Zealand animal and originates from a small island in New Caledonia, where other members of the group exist.

Dr Alain Delcourt holding the taxiderm specimen of H. delcourti that he brought to scientific attention in 1979 (Photo found on numerous websites online, e.g. here; © owner unknown to me – reproduced here on a strictly educational, non-commercial Fair Use basis only)

Worthy failed to specify, however, that there are a number of small isles lying off the two much larger, principal islands constituting New Zealand that definitely fall into his category of "very localised habitats that have not yet been explored by palaeontologists". Could it be, therefore, that the single recorded H. delcourti specimen originated from one of these smaller offshore NZ islands? To my mind, it certainly seems more parsimonious to assume that, as a Hoplodactylus species, Delcourt's giant gecko should have a provenance somewhere within New Zealand than beyond it, i.e. on an island of New Caledonia, or elsewhere.

In addition, if this species were rare or very rare anyway, the chances that fossil remains of it will even exist, let alone be discovered, will necessarily be much less likely than for more common, widely-distributed species. Also of note here is that if Worthy's assertion that H. delcourti was probably not native to New Zealand is correct, then its striking resemblance to the Maoris' mythical kawekaweau is a truly extraordinary and very formidable coincidence.

Drawing of a kawekaweau in a tree (© Hodari Nundu)

At least 150 years have passed since the type – and still the only known – specimen of H. delcourti was collected somewhere in the wild, but the many mysteries that have enshrouded it ever since still seem as impenetrable today as they did back then. Where was it collected, and by whom, is it one and the same as the mythical kawekaweau, why have no additional specimens or remains (modern-day or fossilised) ever been procured, and could there still be living specimens awaiting discovery somewhere out there?

Perhaps one day we shall have answers to some or even all of these questions. Until then, however, we have only Marseilles's long-ignored taxiderm exhibit to remind us of this most mystifying chapter in herpetological history – and just like all such exhibits, it is remaining resolutely reticent.

Rodrigues giant day gecko Phelsuma gigas, sculpture by Nick Bibby (Photo © Dr Karl Shuker)

NB – Some gecko coverages state that the world's largest modern-day gecko species was actually the now-extinct Rodrigues day gecko Phelsuma gigas, once native to the Mascarene island of Rodrigues and various tiny offshore islets but last collected in 1842. However, although its snout-tip-to-vent length could exceed that of the only known specimen of H. delcourti (14.6 in), its total length (i.e. from snout-tip to tail-tip) was less.

This ShukerNature blog article is adapted and updated from my account of Delcourt's giant gecko contained within my book The Encyclopaedia of New and Rediscovered Animals.

THE JAWS OF MEGALODON - SHARK OF NIGHTMARE...AND REALITY?

Artistic impression of a megalodon encounter (© William M. Rebsamen)

It was only ever going to be a matter of time before ShukerNature boldly went where it had never gone before, by confronting what may well be not only the most terrifying cryptid of all time but also the most controversial one – the cryptid that dare not speak its name, in fact, because that name is…Megalodon!

Yes indeed, one of the most contentious, divisive subjects in the entire field of cryptozoology must surely be the putative existence into modern times of the giant megalodon shark, judging at least from the many heated, turbo-charged exchanges that it has engendered down through the years. For what it's worth, and more than two decades on from when I first investigated the case, I personally think that this monstrous sea creature's present-day survival is an unlikely prospect, but it is certainly an inordinately interesting one to research, as I rediscovered when preparing its greatly-expanded, updated section within my newest book Still In Search Of Prehistoric Survivors (2016). So now, having adopted in that book the role of devil's advocate (as required per the brief issued by the publishers of its original edition, In Search Of Prehistoric Survivors), this is what I wrote:

The following lines were penned by Victorian naturalist Philip H. Gosse, and appeared in his book The Romance of Natural History (1860):

Half concealed beneath the bony brow, the little green eye gleams with so peculiar an expression of hatred, such a concentration of fiendish malice, of quiet, calm, settled villany, that no other countenance that I have ever seen at all resembles. Though I have seen many a shark, I could never look at that eye without feeling my flesh creep, as it were, on my bones.

This graphic description vividly expresses the galeophobic feelings of many people when confronted with sharks, especially the most feared species of all - Carcharodon carcharias, the great white shark. The world's largest living species of carnivorous fish (excluding plankton-eaters), it is known to attain a total length of up to 21 ft, but unconfirmed sightings of far bigger specimens have occasionally been recorded, mostly in tropical or sub-tropical waters. Could such sharks really exist - and, if they do, could they prove to be something even more terrifying than oversized great whites?

The great white shark (public domain)

In his book Sharks and Rays of Australian Seas (1964), Antipodean ichthyologist Dr David G. Stead documented an astonishing account that had been narrated to him back in 1918 by some fishermen at Port Stephens, New South Wales. They claimed that their heavily-weighted crayfish pots, each measuring 3.5 ft long and containing several crayfishes (each weighing several pounds), had been effortlessly towed away by a ghostly white shark of enormous size. Estimates given by the fishermen ranged from the length of the wharf on which they had been standing, which measured 115 ft, to, in the opinion of one of the men, "300 ft long at least"! Even though Stead discounted these gargantuan estimates as the product of fear, he was clearly impressed by their claim, stating in his book:

In company with the local Fisheries Inspector I questioned many of the men very closely, and they all agreed as to the gigantic stature of the beast...And bear in mind that these were men who were used to the sea and all sorts of weather, and all sorts of sharks as well...They affirmed that the water 'boiled' over a large space when the fish swam past. They were all familiar with whales, which they had often seen passing at sea, but this was a vast shark...these were prosaic and rather stolid men, not given to 'fish stories' nor even to talking at all about their catches. Further, they knew that the person they were talking to (myself) had heard all the fish stories years before!...The local Fisheries Inspector of the time, Mr Paton, agreed with me that it must have been something really gigantic to put these experienced men into such a state of fear and panic.

Surprise and shock at unexpectedly encountering an awesome Moby Dick of the shark world may well have helped to distort their assessment. Yet even if we accordingly allow a very generous margin of exaggeration, the result is still a creature of far greater size than one would expect for the great white shark. Perhaps the most telling aspect of this episode, however, is that the men were so shaken, after seeing whatever it was they saw, that they weighed anchors straight away, fled back to port, and refused to go out to sea again for several days. This is hardly the behaviour that one would expect from people who know that they will not earn any money if they do not go out to sea - unless their story is true, and they really were frightened by a monstrous shark.

Zane Grey (public domain)

An immense shark, sporting a square head, huge pectoral fins, a green-yellow body speckled with a few white spots (encrusted barnacles?), and measuring considerably more in total length than his 35-40-ft boat was spied in 1927 or 1928 by Zane Grey, while sailing off the French Polynesian island of Rangiroa (about 220 miles northeast of Tahiti) in the South Pacific's Tuamotu Archipelago. Grey was a famous, prolific writer of Western novels, but he was also a passionate angler and the author of eight angling books, including Tales of Tahitian Waters (1931), containing his account of his shark sighting.

Yet despite his experience in handling fishes of record-breaking size, Grey was unable to identify this immense specimen. A square head is certainly not reminiscent of a great white shark, of any size, but rather a whale shark Rhincodon typus. This harmless planktivorous species constitutes the world's largest fish of any type, with a maximum confirmed length of 41.5 ft (but likely to attain up to 50 ft), and it does have a very broad, massive head. Then again, read the next report...

In 1933, when about 100 miles northwest of Rangiroa aboard the S.S. Manganui, Grey's son, Loren, also caught sight of a gigantic shark, once again yellowish in colour but flecked with white, which revealed a great brown tail, plus a massive head that seemed to be at least 10-12 ft across, and a total body length estimated by Grey Jnr to be not less than 40-50 ft. However, he was convinced that it was not a whale shark. So what was it?

Whale shark at the Flower Garden Banks National Marine Sanctuary (public domain)

According to traditional beliefs of the Polynesian fishermen who work along the coasts of New South Wales, these waters are frequented by a frightening type of sea creature that they respectfully refer to as the Lord of the Deep. They liken it to a gigantic white shark, measuring about 100 ft in length. Is this what the Greys spied, and could this be what carried away the pots of the lobster fishermen in 1918?

In his book Shark! (1961), Thomas Helm documented his own (undated) encounter with a giant mystery shark. He and some other people were on board his 60-ft trawler in the Caribbean Sea when they spied a huge shark that he claimed was "not an inch less than thirty feet". He was able to estimate this accurately by comparing its length to that of his trawler; and he also noted that when it swam underneath, its pectoral fins were clearly visible on either side of the boat. He and the other eyewitnesses were unable to identify its species, but he stated that it "most closely resembled the [great] white shark".

During the 1970s, a Mrs T. Brinks and her keen sailor husband Dave were sailing their 40-ft boat about 100 miles west of Monterey Bay, California, when they encountered what looked like a great white shark but of huge proportions. When it swam alongside their vessel, they could see that in total length it equalled that of the boat. After a few moments, it veered to the west, swimming underneath their boat before disappearing (they actually felt the boat rise as it swam beneath it). The Brinkses later recalled their encounter with one of Mrs Brinks's work colleagues, Jon Ziegler, from Idaho, who presented the details in a letter published online by Strange Magazine in 2005.

More recently, in Season 3, Episode 7 (entitled 'Mega Jaws'), first screened on 18 March 2009, the cryptozoological TV show MonsterQuest unsuccessfully sought a giant black carnivorous shark occasionally sighted in the Sea of Cortez (Gulf of California), off Mexico's Baja California peninsula. Fisherman witnesses claim that it is 20-60 ft long, resembles a huge great white shark except for its dark colouration and massive tail, and have dubbed it El Demonio Negro ('the Black Demon'). Might it be a melanistic great white (a huge great white that was fairly dark dorsally and measured almost 20 ft long was hauled up out of the Sea of Cortez by commercial fishermen in April 2013, and parts of this sea are now known to serve as a great white shark nursery), or could it be something very different indeed?

Many ichthyologists are willing to consider the possibility that there are larger specimens of great white shark in existence than have so far been verified by science, but some cryptozoologists are far bolder. Their explanation for the Lord of the Deep is far more spectacular - a terrifying prehistoric resurrection, featuring a living leviathan from the ancient waters.

My mother Mary Shuker holding a fossil megalodon tooth with a 2 pence coin alongside it for scale purposes (© Dr Karl Shuker)

The great white shark once had an even bigger relative - the megalodon or megatooth shark C. megalodon ('big tooth'), sometimes placed in its own genus, Carcharocles. Named after its huge teeth, which were triangular in shape, up to 7.25 in high, and edged with sharp serrations, the megalodon was once believed to measure as much as 98 ft long, but this early estimate of its size was later shown to be incorrect, and was refined to a much more sedate yet still unnerving 43 ft. However, after various extra-large megalodon teeth, some almost 6 in long, were unearthed a while ago at the aptly-dubbed Sharktooth Hill near Bakersfield, California, ichthyologists conceded that certain specimens might have attained a total length of up to 55 ft.

The megalodon is presently known almost entirely from its huge teeth and some individual vertebrae. However, one notable exception is an associated vertebral column of approximately 150 individual centra (vertebra bodies) that range in state from fragmentary to nearly complete. In the major monograph Great White Sharks: The Biology of Carcharodon carcharias (1996), edited by Drs A. Peter Klimley and David G. Ainley, shark experts Drs Michael D. Gottfried, Leonard J.V. Compagno, and S. Curtis Bowman suggested on the basis of the previously-mentioned vertebral column's dimensions and other megalodon remains that in order to support its substantial dentition, the megalodon's jaws would have been "somewhat more robust, larger, and thicker, and with correspondingly more massive muscles to operate them" than those of the great white shark. In overall appearance, they proposed that the megalodon "would likely have had a streamlined, fusiform shape similar to, but more robust than, the [great] white shark and other lamnids, with more bulging jaws and a broader, blunter, and relatively more massive head".

If this reconstruction is accurate, might it explain the Greys' comments about the massive or square-shaped head of their respective giant mystery sharks? Moreover, it is believed that the fins of the megalodon were proportional to its larger size, and hence were bigger than those of the great white. Could this therefore explain the huge pectoral fins sported by the giant mystery shark sighted by Zane Grey?

Once believed to be an exclusively near-surface, continental shelf dweller in tropical and subtropical seas, the megalodon is now thought to have been sufficiently adaptable to have inhabited a wide range of environments, from shallow coastal waters and swampy coastal lagoons to sandy littorals and offshore deepwater abodes, exhibiting a transient lifestyle, and of near-cosmopolitan geographical distribution. Adult specimens, however, were not common in shallow-water habitats (thus explaining the relative rarity of modern-day Lord of the Deep and other super-sized great white lookalike sightings?), and mostly lurked offshore, but may have moved between coastal and oceanic habitats during different stages of the life cycle.

Alongside a life-sized recreation of megalodon jaws (© Dr Karl Shuker)

The megalodon first appeared in the fossil record around 16 million years ago during the mid-Miocene, and was undoubtedly one of the most formidable marine predators of all time. So why, according to mainstream zoology, did it become extinct (if, indeed, it did!)? As yet, there is no definitive answer to this key question. However, the cooling of the oceans that occurred during the late Pliocene and Pleistocene in conjunction with the Ice Ages (an occurrence not conducive to the megalodon's survival, as it favoured warmer, tropical waters), coupled with the resulting migration towards colder, high-latitude regions by the larger whales that constituted its preferred prey (megalodon tooth marks on the fossil bones of such cetaceans are well documented), is the scenario most favoured as the cause of this giant shark's apparent extinction. Also, during the Ice Ages a substantial volume of seawater became locked inside continental ice sheets, thereby resulting in a significant worldwide fall in sea levels, which is something else that was not compatible with megalodon survival, restricting the number of nursery sites available for its juveniles' safe maturation.

Yet in view of how adaptable the megalodon was in terms of the variety of marine environments that it could inhabit, might it have once again been sufficiently adaptable to withstand these changes? True, the fossil record does not contain ample evidence of its survival in regions where water temperatures had significantly declined during the Pliocene. Then again, as pointed out by Gottfried et al., this species may have existed in environments "...that have gone unrecognized due to preservational and/or collecting biases" – a significant but all-too-often ignored or neglected factor when making assumptions based upon the known fossil record.

Also, in view of the several exceedingly large whale species existing then, and still today (the whale hunting industry's depredations notwithstanding), the megalodon would not be short of suitable prey (big cetaceans, along with pinnipeds and fish too, are believed to have constituted its preferred diet). And what if, like the huge carnivorous sperm whale, it also sought out sizeable deepwater species such as giant squids, common in tropical as well as temperate seas, but for which, as is often true from deepwater habitats, there would be little if any readily available confirmation from the fossil record?

Megalodon tooth with two great white shark teeth and a metric ruler (© Kalan/Parzi/Wikipedia - CC BY-SA 3.0 licence)

Even if faced with competition from today's largest carnivorous cetaceans, might there still be enough suitable prey out there in the vast oceans to sustain a viable megalodon population? After all, even large migratory whales like the blue whale and grey whale still spend part of their year in sub-tropical waters; and during those periods that these cetaceans spend in more polar zones, megalodons could subsist instead upon big fishes like the basking shark, whale shark, and abundant smaller species existing in sizeable shoals, plus giant squids.

Irrespective of the precise reason(s) why it died out, the findings of a 2014 study by American researchers Drs Catalina Pimiento and Christopher F. Clements (published by the journal PLoS ONE) suggest that the megalodon most likely did so approximately 2.6 million years ago, during the late Pliocene (a few have opined that it may have persisted into the early Pleistocene). However, these dates fail to take into account a dramatic, highly controversial revelation that occurred at the close of the 1950s. Back in 1875, the British oceanographic survey vessel H.M.S. Challenger had hauled up two megalodon teeth from the manganese dioxide-rich red clay deposit at a depth of 14,000 ft on the sea bed south of Tahiti in the Pacific Ocean. When, in 1959, these teeth were dated by Russian scientist Dr Wladimir Tschernezky, the scientific world received a considerable shock. Knowing the rate of formation of the manganese dioxide layer covering them, he had measured the thickness of the layer - and from the results that he had obtained, he announced in a paper published on 24 October 1959 in the prestigious scientific journal Nature that one of the teeth was only 24,000 years old, and the other was a mere 11,000 years old.

In short, if Tschernezky's results were accurate, the megalodon shark was still alive at the end of the Pleistocene epoch 11,700 years ago. And if this is true, it would again lend credibility to speculation among some cryptozoologists that this incredible species may still be alive today. It is nothing if not intriguing, incidentally, that these two enigmatic teeth were obtained in much the same (Tahitian) locality as that of the giant sharks respectively encountered by the Greys. Just a coincidence?

HMS Challenger, 1858 engraving (public domain)

Having said that, there remains much contention among current ichthyologists and palaeontologists regarding Tschernezky's results. The main argument against them is that the teeth may have originally been reworked from older strata, as has been discussed earlier in this present book with respect to various alleged post-Mesozoic dinosaur and plesiosaur fossils. Also, there can be considerable variation in results obtained for the dating of manganese dioxide deposits, depending upon whether maximum or minimum deposition rates for them are being used, and such deposits also vary in relation to a number of fluctuating external factors such as the concentration in seawater of iron ions and photosynthesising plankton. Whether such variations can be so extreme as to yield a date as recent as only 11,000 years ago as opposed to one of at least 2.6 million years ago, conversely, has yet to be confirmed.

Also worthy of note here is the following statement from the earlier-cited paper by Pimiento and Clements:

In a very small proportion of simulations (1.5%), the inferred date of extinction fell after 0.1 Ma. In six simulations (0.06%) the inferred date of extinction fell after the present day (and thus the species could not be considered as extinct). However, because in the vast majority of the 10,000 simulations (>99.9%) the extinction time was inferred to have occurred before the present day, we reject the null hypothesis (that the species is extant) and the popular claims of present day survival of C. megalodon.

In short, although too small in number to be considered statistically significant, from the vast array of fossil samples utilised in their simulations a few modern-day inferred extinction dates did occur, as well as some with an inferred extinction date of under 100,000 years. How can these be explained and which specific samples were responsible, I wonder?

All in all, if they still exist it would be very interesting to see those two teeth that were dated so contentiously by Tschernezky back in the late 1950s subjected now to modern-day dating techniques. The most common method for Quaternary (Pleistocene and Holocene) remains – which these teeth would be if Tschernezky's age estimates for them of 24,000 and 11,000 years respectively are correct – is radiocarbon (carbon-14) dating, but it generally cannot date specimens older than around 60,000 years. However, a more recent and potentially much more useful technique, which has already been proved to be effective with fossil teeth, is electron paramagnetic resonance (EPR).

As noted in a 14 February 2014 Spectroscopy Europe online paper authored by Dr Mathieu Duval from the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) in Burgos, Spain, optimum time range application for EPR dating of tooth enamel lies between c.50,000 years and c.800,000 years. Moreover, in some specific conditions, the real time-range limits for EPR dating may be potentially pushed from present-day to around 2–3 million years. This means that EPR dating not only could demonstrate unequivocally whether Tschernezky's unexpectedly recent age estimates for these two very contentious megalodon teeth were correct, but also might still be able to provide an age for them even if they actually do date back to the time of the megalodon's official demise, i.e. approximately 2.6 million years ago – something that radiocarbon dating could not achieve.

A white fossil megalodon tooth (public domain)

One final comment regarding giant, ostensibly anachronistic shark teeth: in his authoritative work The Fishes of Australia Part 1: The Sharks, Rays, Devil-Fish, and Other Primitive Fishes of Australia and New Zealand (1940), Gilbert P. Whitley, then Curator of Fishes at the Natural History Museum in Sydney, Australia, stated:

Fresh-looking [megalodon] teeth measuring 4 by 3 1/4 inches have been dredged from the sea floor, which indicates that if not actually still living, this gigantic species must have become extinct within a recent period.

Unfortunately, he didn't provide further details concerning these bold claims. Fossil megalodon teeth are generally black or grey, less commonly brown and even gold, but white specimens are also known – and although they too are fossilised, these latter ones can look deceptively recent in appearance, so Whitley may have been mistaken. As for the teeth noted by him, sadly I have no knowledge of where they currently reside.

Megalodon vs the giant pliosaur Liopleurodon (© Hodari Nundu)

In summary: Dr Stead considered that the shark responsible for towing away the fishermens' lobster pots could have been a living megalodon, but just how likely is this terrifying prospect? I am well aware that by virtue of its very nature, the megalodon must surely appear to be one of this book's least likely creatures to survive in the present day. Having said that: if, as noted here, this monstrous carnivorous shark dined upon large whales, pinnipeds, fishes, and (especially) giant squids, moving up and down through the sea depths in search of its varied prey, its huge food requirements could surely be met. And if, as predicted from palaeontological studies, it only occasionally entered the oceans' surface waters as an adult, this might explain how in spite of its great size it has succeeded in eluding science, and why even fishermen in its general area of distribution only rarely catch sight of it.

Certainly, as someone who in 2008 flew from Santiago in Chile to Easter Island and, in so doing, spent no less than 4 hours travelling continuously across a seemingly limitless blue expanse of water with never so much as the tiniest speck of land in sight, yet knowing full well that this was in reality only a minute portion of the Pacific's full mid-oceanic extent, I feel qualified to offer the opinion that in such an unimaginably vast yet (for the greater part) only sparsely visited expanse of water relatively speaking, even creatures as huge as megalodons could surely exist just beneath the surface without ever being seen by humans for much if not all of their life. Here they could readily avoid the occasional cruiser or other sizeable sea vessel crossing the immense mid-ocean stretches of water upon which the various Pacific island groups are scattered like mere confetti, and only occasionally approach the shores of such islands where they may conceivably attract brief attention before travelling back out to the open seas once more.

We know that in Pliocene times megalodons occurred in coastal waters (albeit only rarely as adults), because the fossil record tells us so. But what if megalodons also lived in mid-oceanic stretches where any dead specimens either were consumed by other marine carnivores or became fossilised in locations where such remains can never be uncovered, such as the sea bottom – except, possibly, for a few anachronistic teeth dredged up by a research vessel?

Artistic impression of a megalodon pursuing two Eobalaenoptera whales (© Karen Carr-Wikipedia - CC BY-SA 3.0 licence)

And even if such a creature is spied once in a while when far out to sea, by some ocean-going tourists or bold fishermen venturing further out than usual from their coastal zone, what will they see? Just a triangular dorsal fin resembling a slightly larger-than-normal great white's, cutting silently through the water? Who would think to report that as anything special?

However, one could also argue that if the megalodon has indeed survived into the modern day, why was it not reported by whalers during the whaling age? Great white sharks were frequently attracted to harpooned, massively-bleeding whales, sometimes causing problems for whalers trying to land these huge, dying sea mammals or their carcases. How much greater a problem, therefore, would megalodons have posed? Yet I am not aware of any whaling records describing encounters with sharks that might have been megalodons.

As for smaller, juvenile megalodons, surely these would be hooked or entangled in netting from time to time, just like similar-sized adult great whites are? Yet again, however, there do not appear to be records of this, unless any such juveniles that may have been caught looked similar enough to adult great whites for anglers not to have considered them worthy of being brought to zoological attention?

Fossil whale vertebra bitten in half by a megalodon and bearing deep tooth-mark grooves from it (© Jayson Kowinsky/Wikipedia - CC BY 3.0 licence)

Also, if the megalodon still exists there would surely be big whales out there that have survived a megalodon attack yet carry the scars created by such a monster's huge teeth, but again I am unaware of any records of this. Then again, any whale surviving a megalodon attack would need to be very big indeed, and such individuals probably remain far out of sight in the open oceans, and those not surviving such an attack would be devoured by the victorious megalodon, with any remains simply sinking to the ocean floor.

Yet another anomaly if the megalodon is indeed still alive today is why no modern-day megalodon teeth have ever been found, bearing in mind that sharks shed numerous teeth every year, and that assemblages of shark teeth from other species have been procured from the sea floor. Then again, perhaps some modern megalodon teeth have been obtained, but, in view of how sought-after their fossil equivalents are by collectors (and expensive too!), have simply not been publicly revealed.

Having said all of this, there is a notable modern-day precedent for large sharks remaining hidden from science. In November 1976, a major new species of very large shark was accidentally captured by a research vessel anchored off the Hawaiian island of Oahu. Attempting to swallow one of the ship's parachute anchors, it had choked to death, despite its enormous mouth, which swiftly earned its species a very appropriate name - the megamouth shark Megachasma pelagios. Measuring up to 18 ft long, this very distinctive species has since been recorded from waters all around the world, and observations of living specimens fitted with tracking devices have revealed that it undergoes vertical migration - staying in the depths of the sea during the day, and rising to the surface only at night. This explains how such a large and widely-distributed shark species had successfully managed to evade scientific detection until as late a date as 1976.

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

In fact, a megamouth – or some other very large, formally undescribed species of deepwater shark – may actually have been seen and photographed by a scientific team a full 10 years earlier. On 15 August 1966, the San Mateo Times, a Californian newspaper, carried the following very intriguing report:

Undersea cameras of the Scripps Institute of Oceanogra­phy have photographed a colossal shark-like fish that is unfa­miliar and may prefer living in the darkest depths of the Pacific.

Scripps' Dr. John D. Isaacs, speaking at a weekend confer­ence, estimated the fish at 15-20 feet in length and three to six feet thick at its widest.

The species could not be determined, he said, because of the unmanned camera's limited field which only allowed pictur­ing the fish's gills and pectoral fin.

"It is probably a shark, but a shark the likes of which we have never seen before," he said. The fish was photographed at a depth of 6,OOO feet off San Clemente Island, which is about 75 miles south of Los Angeles.

Since the first megamouth was caught off Oahu in 1976, several have been washed ashore or documented in waters off California, lending further support to the possibility that the Scripps's mystery shark was a specimen of this very big species – always assuming, of course, that it wasn't a juvenile megalodon...?

Incidentally, crypto-sceptics have suggested that the megalodon could not exist as a deepwater species because it would require all manner of morphological specialisations, but in view of the fact that the only physical remains that we have of it are teeth and vertebrae, how can anyone say with certainty that it didn't – or doesn't – possess any such specialisations?

Bearing in mind, therefore, that a mere 40 years ago the megamouth was still unseen and undiscovered by science, the prospect for prehistoric persistence of the megalodon cannot be entirely denied out of hand – however much we may wish to banish from our minds the disturbing image of a rapacious, flesh-eating shark at least twice the size of the current record-holder for the great white, cruising anonymously beneath the surface of the Pacific in the 21^st Century.

Megalodon shark (grey for maximum estimate, red for conservative estimate), whale shark (violet), great white shark (green), and human (black), to scale (© Scarlet23/Wikipedia - CC BY-SA 3.0 licence)

Last – and least – of all but requiring a mention here if only because of how much confusion it caused (and still causes) among viewers not well-versed in cryptozoology is the infamous 'mockumentary'/'docufiction' Megalodon: The Monster Shark Lives, which was first aired on the American TV network Discovery Channel in 2013, concerning the alleged modern-day survival of this giant shark species. The programme has an entry on Wikipedia that summarises its history very succinctly as follows:

The story, with only short disclaimers at the beginning and ending indicating that it is fictional, revolves around the loss of a pleasure boat and crew off the coast of South Africa and an ensuing investigation that points to an attack by a member of the species megalodon, a prehistoric shark thought to be long extinct. Its format is that of a documentary that includes accounts of "professionals" in various fields related to Megalodon. It follows a similar format to another docufiction aired by Discovery Channel, Mermaids: The Body Found.

The show, like Mermaids, came under equal criticism and scrutiny by both scientists and ordinary viewers due to the attempt to present fiction as a non-fiction documentary. Despite the disclaimers, some people actually believed they were watching a real documentary while others were offended that a docufiction show would be aired on a channel that had been known for true science shows. It should also be noted [that], unlike Mermaids, the disclaimers were barely even present, in addition to the talk show that was strongly saying and asking if people believed what was presented in Megalodon showed that the species was still alive. This misinformation likely caused the mass misconception that the shark species was still alive.

No it didn't – speculation on this subject was rife long before the programme was produced. As for whether the modern-day existence of the megalodon actually is – or is not – a misconception, this has already been discussed soberly and at length in the present section of this book. In my opinion, however, any attempt to do so in an equally rational, objective manner elsewhere is always likely to be overshadowed nowadays by the Discovery mockumentary's unhelpful contribution to the subject, which is a tragedy for those seeking to bestow gravitas and credibility upon serious cryptozoological debate.

This ShukerNature blog article on the megalodon is exclusively excerpted from my recent mega-book Still In Search Of Prehistoric Survivors: The Creatures That Time Forgot? (Coachwhip Publications: Darke County, 2016).