It has always been rumoured that some snakes grow to sizes that exceed the 10 m record generally accepted as the authenticated maximum: this was for a Reticulated python Python reticulatus shot on Sulawesi in 1912. Numerous stories and anecdotes discuss Reticulated pythons and anacondas Eunectes murinus that far exceed this, with the most famous of these stories being Major Percy Fawcett’s 19 m long anaconda that he claimed to have shot in the Brazilian Rio Abuna in 1907 [scene depicted in adjacent image]. Despite its immense length, Fawcett reported that this snake had a width of just 30 cm (which makes the tale rather unbelievable), and he even discussed trails in the swamps that ‘support the statements of Indians and rubber pickers that the anaconda sometimes reaches an incredible size, altogether dwarfing that shot by me’ (Heuvelmans 1995, p. 340). Despite these many stories, no-one has yet produced a snake that exceeds 10 m in total length (though I hope that – if such a specimen is ever found, it is not killed, but is restrained or captured or something.. and yes I do know that this is somewhat less easy than it sounds).
Perhaps less well known than these accounts of modern-day giants, however, are rumours and reports of fossil snake bones that have been estimated by some workers to have belonged to truly gargantuan reptiles…
As is always the case when several large-bodied members of a group are known, experts disagree over which of the several contenders is ‘the biggest’. Among fossil snakes, the disagreement has centred over Gigantophis garstini of Upper Eocene Egypt and Libya*, first described by Charles William Andrews in 1901 (Andrews 1901, Hoffstetter 1961), and Palaeophis colossaeus from the Eocene of Mali, named by Jean-Claude Rage in 1983 (Rage 1983). Gigantophis is today regarded as a madtsoiid**: this is a group of controversial archaic snakes whose fossil record extends from the Upper Cretaceous to the late Pleistocene (though they only survived beyond the Eocene in Australia). Snake workers differ in their interpretation of where madtsoiids fit within snake phylogeny, but that’s a debate that I want to avoid here (see Rieppel et al. 2002, Scanlon 2003, 2005, 2006, Scanlon & Lee 2000, 2002). Palaeophis belongs to the palaeophiids, a group of unusual marine snakes known from the Cretaceous to the Eocene. They also appear to be archaic and may be among the most basal snakes known: I don’t want to say too much about them, as a blog article devoted to them alone is due to appear soon.
* It now seems that some of the Fayum deposits conventionally regarded as Upper Eocene are Lower Oligocene (Seiffert 2006). I do not know if this affects the age of Gigantophis.
** Incidentally, how are you supposed to pronounce this word? I say it ‘mad-tee-soy-id’.
So how big were these snakes? Gigantophis has generally been given a length of about 9 m, but Rage (1983) suggested that Palaeophis colossaeus might have exceeded this and thus been the biggest snake of all time. Whether he meant that it exceeded 10 m isn’t clear, but note that even these mega-huge snakes are either smaller than, or not much bigger than, the biggest, record-holding living snakes. Jason Head and David Polly recently used morphometric techniques to provide more thorough length estimates for Gigantophis: using the proportions of modern snakes as a template, their regression analysis of body length against vertebral size (this taxon is only known from isolated vertebrae) suggested a total length of 9.3-10.7 m ‘indicating that this is the largest snake for which such an analysis can be performed’ (Head & Polly 2004) [adjacent image of Gigantophis, to scale with a person, from here].
The authors didn’t fail to make note of the fact that Gigantophis lived alongside a diverse assemblage of basal proboscideans, big hyracoids, amphibious artiodactyls and other taxa, and it is tempting to speculate that this immense snake preyed upon some of the larger mammals in this community. The Upper Eocene/Lower Oligocene of Fayum was also home to enigmatic giant flightless birds (Eremopezus), the bizarre ptolemaiids, early macroscelideans, big creodonts, archaic primates and many other neat taxa [image below shows Gigantophis eating a moerithere, from here. It is sometimes said in the literature that madtsoiids couldn't distend their jaws in the same manner as extant snakes, so I don't know if a feat like this was really possible].
As fossil snakes go, Gigantophis is reasonably well known, and deservedly so given its size. Little discussed, however, are a few other, far more obscure candidates for the title ‘largest ever snake’. In a paper on Brazilian sebecosuchians, Zulma Gasparini and colleagues (1993) made a brief passing mention to ‘huge booids up to 29 meters in length’. Cough splutter… 29 m?? They chose not to elaborate on this interesting observation, and only cited Adriana Albino’s 1989 doctoral thesis, which I haven’t seen. Also in 1993, Albino described the new boid Chubutophis grandis from the Eocene of Chubut Province, Argentina. Unfortunately C. grandis is known only from a partial body vertebra. However, it is especially big and a few features suggest that it’s from a juvenile. Albino wrote ‘Considering that this material is from a young specimen, its size is extraordinary and it is estimated that the adult would have reached greater dimensions than those observed in the largest snakes known up to the present, including Madtsoia and Gigantophis‘ (Albino 1993, p. 60). Elsewhere in the same paper, Albino noted that Madtsoia ‘was probably 10 m long’ (p. 63) and again made the point that the adult form of Chubutophis ‘would have surpassed Madtsoia in length’. A 10 m length estimate for Madtsoia is interesting: one of the largest species in the genus, M. bai from the Eocene of Argentina has been estimated at 7-8 m (Smith 1990), but I haven’t seen the 10 m estimate elsewhere.
I therefore wonder if C. grandis is the same thing as the ’29 m long’ boid referred to by Gasparini et al. (1993). In 1999 I asked Jean-Claude Rage about these giant snakes. He informed me of a 1991 popular article by Albino (note: a popular article and not a technical paper) in which it was suggested that the biggest ever snakes reached lengths of between 15 and 20 m. In this article Albino discussed: (1) a juvenile snake from Eocene Argentina estimated to have been 5-7 m long, and in adult form 10-12 m long; and (2) another Argentinean snake known only from an incomplete vertebra, estimated to belong to a snake with a head 70 cm long, and a total length of 15-20 m (Rage suggested that the 29 m length given by Gasparini et al. (1993) might be a typo). Unfortunately the age of the second form is unknown. It seems that the first snake Rage referred to was Chubutophis but, if this is true, then Albino wrote of two different really huge snakes. I therefore confess to being confused and I suppose the only person who could sort it out would be Dr Albino: despite attempts a while back to contact her though, I was unsuccessful. I asked Jason Head what he thought about the possibility of a 29 m long fossil snake. His answer was that such a creature was highly unlikely to have existed, given various constraints (though his actual language was a bit more colourful: we were in a bar at the time) [adjacent image shows pretend anaconda from the god-awful movie of the same name. Didn't it star Jennifer Lopez?].
For the record, I agree with Jason that snakes exceeding 15 m in length almost certainly never existed, but I still want to know why a qualified fossil snake expert would say, on more than one occasion, that they did. At least one noted expert on fossil snakes is a regular visitor here at Tetrapod Zoology. At the risk of putting him on the spot, any more information would be gratefully received.
Finally, obviously this isn’t the ‘new mammal diversity’ article I’ve been plugging lately. Like cassowaries kick ass, this post has appeared out of lack of time and desperation to post something new: it was a bit of old text that only took a short while to update. Dammit, if only I didn’t have to work.
Refs – –
Albino, A. M. 1991. Las serpientes del Santacrucense y Friasense de Argentina. Ameghiniana 28 (3-4), 402.
– . 1993. Snakes from the Paleocene and Eocene of Patagonia (Argentina): paleoecology and coevolution with mammals. Historical Biology 7, 51-69.
– . 2000. New record of snakes from the Cretaceous of Patagonia (Argentina). Geodiversitas 22, 247-253.
Andrews, C. W. 1901. Preliminary note on some recently discovered extinct vertebrates from Egypt (Part II). Geological Magazine (Dec. 4) 8, 434-444.
Gasparini, Z. 1993. New Tertiary sebecosuchians (Crocodylomorpha) from South America: phylogenetic implications. Historical Biology 7, 1-19.
Head, J. & Polly, D. 2004. They might be giants: morphometric methods for reconstructing body size in the world’s largest snakes. Journal of Vertebrate Paleontology 24 (Supp. 3), 68A-69A.
Heuvelmans, B. 1995. On the Track of Unknown Animals. Kegan Paul International, London.
Hoffstetter, R. 1961. Nouvelles récoltes de serpents fossils dans l’Éocène supérieur du désert Libyque. Bulletin du Muséum National d’Histoire Naturelle, 2e Serie 33 (3), 326-331.
Rage, J.-C. 1983. Palaeophis colossaeus nov. sp. from the Eocene of Mali, with remarks on the genus problem within the Palaeophinae. Comptes Rendu de l’Academie des Sciences, Paris, Serie II 296, 1741-1744.
Rieppel, O., Kluge, A. G. & Zaher, H. 2002. Testing the phylogenetic relationships of the Pleistocene snake Wonambi naracoortensis Smith. Journal of Vertebrate Paleontology 22, 812-829.
Scanlon, J. D. 2003. The basicranial morphology of madtsoiid snakes (Squamata, Ophidia) and the earliest Alethinophidia (Serpentes). Journal of Vertebrate Paleontology 23, 971-976.
– . 2005. Cranial morphology of the Plio-Pleistocene giant madtsoiid snake Wonambi naracoortensis. Acta Palaeontologica Polonica 50, 139-180.
– . 2006. Skull of the large non-macrostomatan snake Yurlunggur from the Australian Oligo-Miocene. Nature 439, 839-842.
– . & Lee, M. S. Y. 2000. The Pleistocene serpent Wonambi and the early evolution of snakes. Nature 403, 416-420.
– . & Lee, M. S. Y. 2002. Varanoid-like dentition in primitive snakes (Madtsoiidae).
Journal of Herpetology 36, 100-106.
Seiffert, E. R. 2006. Revised age estimates from the later Paleogene mammal faunas of Egypt and Oman. Proceedings of the National Academy of Sciences 103, 5000-5005.
Smith, M. J. 1990. Wonambi naracoortensis. In Rich, P. V. & van Tets, G. F. (eds) Kadimaka. Extinct Vertebrates of Australia. Princeton University Press (Princeton, New Jersey), pp. 156-159.