Encyclopaedia of Cryptozoology

Illustrations of five of Heuvelmans' sea serpent categories from Creatures From Elsewhere (1984). Clockwise from upper left: many-finned sea serpent, long-necked seal, merhorse, super-otter, and many-humped sea serpent.

The Heuvelmans system is a system of categorising sea serpent sightings developed by Bernard Heuvelmans in Le Grand Serpent-de-Mer (1965) and In the Wake of Sea Serpents (1968).[1][2] After examining 587 sightings from 1639 to 1966, Heuvelmans concluded that there were at least nine major types of unknown animals involved. These nine Heuvelmans types are the long-necked, merhorse, many-humped, many-finned, super-otter, super-eel, marine saurian, father-of-all-the-turtles, and yellow belly,[3] with giant invertebrates added later.[2]

Following A. C. Oudemans' study of The Great Sea-Serpent (1892), which presented a single animal, Megophias, as the explanation for all otherwise-unexplained sightings, the Heuvelmans system was the first attempt at creating a comprehensive classification scheme for sea serpents. Many of Heuvelmans' types and especially their possible identities are controversial, and more recent researchers have attempted to improve on his system, or present alternative systems such as the Mangiacopra system, Coleman-Huyghe system, and Champagne system.[4][1]


Of the 587 sightings he examined, Heuvelmans concluded that 121 were "vague and therefore doubtful," 56 were false reports based on 49 deliberate hoaxes, 52 were certain or probable cases of mistaken identity, 9 were "incomprehensible, unclassifiable or very suspect," and 41 were unclassifiable periscopes (either longnecks or super-eels). The remaining 308 sightings were automatically assigned by a computer to Heuvelmans' nine types, with varying degrees of certainty.[3] Some of Heuvelmans' theories were informed by Ivan T. Sanderson's own research and theories.[5]

According to Heuvelmans, if he felt that a sighting could be plausibly explained by a known species, but the identification was not certain, he chose to discard it rather than allow it to contaminate his data. A number of cases were also classified as deliberate hoaxes, including well-known sightings such as the Monongahela serpent, moha-moha, and Hook Island serpent.[3]


Where Heuvelmans felt reasonably sure of a type's identity, he assigned it a binomial name (i.e. Megalotaria longicollis for the longneck),[3] later arguing that such names should be viewed in the same manner as the parataxonomic names assigned to trace fossils (i.e. Diplichnites, probable arthropleurid trackways, or Chirotherium, a probable pseudosuchian trackway).[6] While the granting of binomial names to cryptids is controversial, it has been suggested that Heuvelmans' practice was not necessarily at odds with the rules of the International Commission on Zoological Nomenclature, leaving his names in a place of ambiguous validity.[7]


Image Name Range Heuvelmans' identity Equivalents in other systems
Megalotaria longicollis, Monique Watteau.jpg
Long-necked sea serpent
(Megalotaria longicollis)
Cosmopolitan Long-necked seal
Merhorse, ITWOSS.jpg
(Halshippus olai-magni)
Atlantic and Pacific Oceans Long-necked seal
Many-finned sea serpent, ITWOSS.jpg
Many-finned sea serpent
(Cetioscolopendra aeliani)
Cosmopolitan in tropical waters Cetacean
Many-humped sea serpent, ITWOSS.jpg
Many-humped sea serpent
(Plurigibbosus novaeangliae)
North Atlantic Ocean Cetacean
Super otter Coudray.png
(Hyperhydra egedei)
Norwegian and Barents Seas Primordial cetacean
Super-eel Coudray.png
Super-eel Cosmopolitan Eel or selachian
Gambo Philippe Coudray.png
Marine saurian Cosmopolitan in tropical and subtropical waters Thalattosuchian or mosasaur
Father-of-all-the-turtles Atlantic Ocean and Caribbean Sea
Yellow One Coudray.png
Yellow belly Indian and Pacific Oceans Possible shark or amphibian


Ulrich Magin, who holds the sea serpent to be "a cultural beast, like the mermaid, the dragon and the unicorn," argues that Heuvelmans would often use a single physical or geographic characteristic for his classifications; for example, classifying all maned animals as merhorses, and all Scandinavian sea serpents as super-otters. According to Magin, the Heuvelmans system cannot handle sightings in which multiple diagnostic characteristics, such as a long neck, a mane, and many humps, were mentioned.[4] Richard Freeman argues that Heuvelmans was biased in favour of marine mammal identities, and that he struggled with sightings describing reptilian features on types which he believed to be mammals (such as the many-humped).[8]

Karl Shuker argues that Heuvelmans placed too much faith in the accuracy and precision of eyewitness testimony, leading him to make "bold claims and intricate deductions" and highly-detailed descriptions of the appearance and behaviour of his types.[9] Most of Heuvelmans' types have been subject to more specific criticisms regarding either his methodology or his suggested identifications,[10] and Heuvelmans himself found the existence of the father-of-all-the-turtles dubious,[3] eventually abandoning both it and the yellow belly.[11][2] Paul H. LeBlond and John Sibert found that the Heuvelmans system was not useful in examining Cadborosaurus sightings off British Columbia, leading them to create a local, three-type classification system for these reports.[12]


Apart from general debates regarding the types' validity and possible identities, two major amendments to the Heuvelmans system have been proposed, by Michael Woodley and Dale A. Drinnon. Woodley's amendment, in In the Wake of Bernard Heuvelmans (2008), voids the yellow belly and father-of-all-the-turtles, and reinterprets the many-finned as a marine arthropleurid myriapod, the marine saurian as a zeuglodon or protocetid, and the many-humped and super-otter as giant sea otters.[2]

Dale A. Drinnon voids the super-otter, many-humped, and many-finned; synonymises the longneck and merhorse as the "plesiosaurian sea serpent"; and reinterprets the yellow belly as an elongated shark with a thresher-like tail. He retains the marine saurian, super-eel, and father-of-all-the-turtles, renamed the "mosasaurian sea serpent," "eel-like sea serpent," and "chelonian sea serpent." The former two are split into multiple subcategories based on size.[13][14]

Notes and references[]

  1. 1.0 1.1 Eberhart, George M. (2002) Mysterious Creatures: A Guide to Cryptozoology, ABC-CLIO, Inc., ISBN 1576072835
  2. 2.0 2.1 2.2 2.3 Woodley, Michael (2008) In the Wake of Bernard Heuvelmans: An Introduction to the History and Future of Sea Serpent Classification, CFZ Press, ISBN 978-1905723201
  3. 3.0 3.1 3.2 3.3 3.4 Heuvelmans, Bernard (1968) In the Wake of the Sea-Serpents, Hart-Davis, ISBN 9780246643124
  4. 4.0 4.1 Coleman, Loren & Huyghe, Patrick (2003) The Field Guide to Lake Monsters, Sea Serpents and Other Mystery Denizens of the Deep, TarcherPerigree, ISBN 978-1585422524
  5. Coleman, Loren (2001) Mysterious America: The Revised Edition, Paraview Press, ISBN 978-1931044059
  6. Heuvelmans, Bernard "What Is Cryptozoology?," Cryptozoology 1 (1982)
  7. Woodley, Michael & Naish, Darren & Shanahan, Hugh P. "How Many Extant Pinniped Species Remain to be Described?," Historical Biology (December 2008)
  8. Freeman, Richard (2019) Adventures in Cryptozoology: Hunting for Yetis, Mongolian Deathworms and Other Not-So-Mythical Monsters, Mango, ISBN 9781642500165
  9. Shuker, Karl P. N. ShukerNature: THE LONG-NECKED SEAL IN CRYPTOZOOLOGY - PART 1: GIRAFFE SEALS AND SEA SERPENTS karlshuker.blogspot.com (28 July 2015) [Accessed 19 February 2019] — Wayback Machine
  10. Shuker, Karl P. N. (2016) Still In Search Of Prehistoric Survivors: The Creatures That Time Forgot?, Coachwhip Publications, ISBN 978-1616463908
  11. Heuvelmans, Bernard "Annotated Checklist of Apparently Unknown Animals With Which Cryptozoology Is Concerned", Cryptozoology, No. 5 (1986)
  12. Mackal, Roy P. (1980) Searching for Hidden Animals: An Inquiry Into Zoological Mysteries, Cadogan Books, ISBN 978-0946313051
  13. Drinnon, Dale A. CRYPTOZOOLOGY ONLINE: Still on the Track: DALE DRINNON: Modifications to the Aquatic Cryptids Classifications as Proposed by Heuvelmans forteanzoology.blogspot.com (27 June 2010) [Accessed 25 October 2020]
  14. Drinnon, Dale A. "Revised Checklist of Cryptozoological Creatures," CFZ Yearbook (2010)