By Rom and Nik Whitaker
The fascination for ‘finding the biggest’ is deeply engrained and when film producer Harry Marshall at Icon Films in the U.K. offered a chance to search for the world’s largest croc who could refuse?
Claims of giant crocs are as wild as those for outsize fish and snakes. “It was longer than the boat”, has been earnestly related in a dozen languages, from the Rift Valley lakes of Ethiopia to the mighty Fly River in Papua New Guinea. And the Fly is where this ‘skull quest’ (for that’s what it’s become) began.
The largest crocodile with photographic documentation
In 1980 I (RW) was working for the United Nations croc program in Papua New Guinea as ‘Production Manager’; the second author (NW) was also there, see illustration.
Nik assists in measuring a record sized saltie skull, PNG
Photo: Rom Whitaker
Along with UN Volunteer Jerome Montague, also a biologist, we went off on patrol down the Fly River, checking on the success of village croc farms, providing water pumps and advice on husbandry. When we arrived at Obo village one sultry afternoon the villagers gathered on the riverbank to greet us and to excitedly show what they had caught the previous morning in a net set for the famous local fish, the barramundi. A huge male saltwater croc had gotten his teeth tangled in the hand-made rope net and drowned. It took 50 men to haul the giant croc out onto the bank (it could have weighed a ton) and when they cut it open there was a whole rusa deer in the stomach. The skin had been salted and rolled up so we flattened it out on the ground and measured it. The total length was 6.20 meters, or a little over 20 feet long! Since it was already a bit dry it might have been a few inches longer.
Skin and skull of the Fly River saltie, PNG
Photos courtesy: Rom Whitaker
The note that Jerome published about this find in “Herp Review” in 1983 didn’t exactly shake the world. People were (and still are) quite convinced that salties well over 20 feet long are on record. But when the quest for the biggest started to get serious, it was soon evident that these ‘records’ are mostly anecdotes with no solid evidence. Some colleagues are ready to accept anecdotal total lengths; we’re much more skeptical.
The 1:7 Hypothesis
Wouldn’t it be just great if you could get the dorsal head (skull) length of a croc, multiply it by a simple number and get the total length? Well, E. Banks (1931), Karl Schmidt (1944), Heinz Wermuth (1964), Angus Bellairs (1969) Allen Greer (1974) and Allan Woodward et al (1995) are some of the authors who concurred that an average ratio for crocodilian head length to total length comes out to close to1:7 using several samples of salties, Niles and American alligators. In this formula, the simple measurement of the skull length is from nose tip to the back of the occipital platform, (see illustration) preferably using a big tree caliper or at least by using a perpendicular steel ruler front and back while laying the tape. (Professional ‘skullers’ will warn that a croc skull will shrink up to 4 % in passing years.)
Courtesy: Phill Hall
Unfortunately some croc workers have taken ‘head length’ to mean from nose tip to back of the mandible (the lower jaw bone which sticks way out behind the skull), adding 25% or more. Other workers routinely measure from nose tip to the back of the occipital condyle which articulates with the spinal column, and this will add a few extra centimetres to the length of a big skull.
However, the 1:7 formula is based mainly on smaller animals with few samples of crocodilians above 4 metres. While gators and broad-snouted crocs like the mugger are relatively ‘stumpy’ animals, and the gharial are at the other linear extreme, salties and American crocs fall in the intermediate range. Wermuth notes that salties have a proportionately longer tail (relative to trunk length) than other crocs and that in salties over 1.5 meters, the head width increases at a proportionately greater rate than trunk length. The other problem is of course that crocs are like us, they grow long when young, then slow down and start growing outward, again complicating the simple ratio.
So there are bound to be serious difficulties when trying to apply the 1:7 to all crocs of all ages. Predictably, though there are some big skulls in collections, there are very few whole skeletons or reliable total lengths to go with these biggest of skulls. A single illustration will serve as an example of the unreliability of historical references: the saltwater croc skull from Luzon, Philippines (killed in the 1880s) measures 71 cm (the dorsal cranial length, not the mandible), a big one indeed. Using the 1:7 ratio that would make it a 4.7 metre croc (a 15 footer!), yet the data card for the skull, repeated ad nauseum in the literature, assures us that it was an amazing 33 feet or ten metres ( plus 4% for shrinkage)! Even with a 1:9 dorsal skull length to total length ratio (which we can confirm some salties indeed have) this saltie couldn’t have been more than 6.5 metres, or 21.5 feet.
Predictably the Aussies (who are sometimes just a bit like Texans, but luckily have no George Bush) claim the biggest crocs, but when you pin them down, again there is little solid evidence. The oft quoted 28 footer killed back in July 1957 by the Pawlowskis in the Norman River Estuary of the Gulf of Carpentaria remains just an unverified anecdote, no matter how many publications the story appears in.
Adam Britton and I (RW) measured two of the largest saltie skulls in Australia, one called ‘Charley’ at the Darwin Croc Farm (a ‘mere’ 64.4 cm) and one shot by Terry Holtz on display at the Corrorboree Tavern near Darwin. This one measures 68.8 cm and is possibly the largest skull in Australia. Driving down the road we stopped in for yet another cold one at Bark Hut Inn, Annaburroo and there we found and measured just the mandible of a saltie 89.9 cm – bigger than the Corroboree mandible. Adam has heard of another croc skull in NT with a mandible of 96 cm (close to the size of the Paris Museum monster croc). The search continues for the largest Aussie skull.
News of an estimated 22 footer has also come from the Bullo River. We did see some 16 footers and one massive slide, but the Bullo giant is still out there.
Back in India there are current stories of 23 footers in Bhitarkanika National Park in the Indian state of Orissa. In fact, someone is such a convincing story teller that the Guinness Book of Records proclaims that this is where the largest croc in the world lives. It could be true, we hope it is, but we need evidence and not another tale of ‘it was bigger than the boat’. Hopefully Guinness does more rigorous verification with their other stories.
The Kanika Skull
Photo: Janaki Lenin
There is, however, some solid evidence of giant crocs here in the form of a couple of skulls, one of them owned by Prince Shivendra, the Raja of the erstwhile principality of Kanika (part of it now included in the National Park, famous for its amazingly successful croc recovery program). A big croc, killed in 1926 on the Dhamra River was said to have been 23 feet long, close to seven metres. The huge skull is the only remaining evidence and at 73.3 cm from nose tip to back of occiput appears to be the largest saltwater croc skull in India and one of the top three in the world. (Note: In 1973 Daniel and Hussain report this skull to be one metre and in 1978 I (RW) reported it as 78cm! Obviously meticulous measurements using tree calipers is the way to go). But if ‘Kalia’ (the name of this giant croc who reportedly ate 13 women – their bangles were recovered from his stomach) was indeed 23 feet long, then the skull length to total length ratio is 1:9.4, far away from the ‘standard’ ratio of 1:7. Another one, found dead in the same river by the Wildlife Department in 2005 has a dorsal cranial length of 66 cm and a total length of about 5.2 m (17 feet) (a ratio of 1:7.9), though the authorities reported that the carcass measured over 5.7 m (19 feet) and the skull 68 cm (a ratio of 8.38). Luckily the entire skeleton was preserved and needs to be carefully re-measured.
To confirm the inapplicability of the 1:7 ratio for big crocs we measured ‘Jaws III’, the 16 foot (4.8m) 38 year old saltie at the Madras Crocodile Bank and the head to total length ratio worked out to be 1:9. If we just had a larger sample size of head to total length in bigger crocs we’d be closer to a realistic ratio. It’s very evident that big crocs (gators too) slow down on linear growth and start getting bulkier at a certain point. Webb and Messel (1978) make the point that it would not be valid to apply the same ratio formulae used in smaller crocs to salties over 4 m. This of course tosses the 1:7 ratio for a loop, though it’s still helpful and somewhat accurate for animals below 4 m, especially when doing size estimates during night counts when all you see is the head.
The biggest saltie skull in the world: Paris Museum
Photos courtesy: Peter Taylor
When we met up at the CSG meeting in Montelimar in June ’06, Peter Taylor promised to blow our minds with details of a spectacular skull at the Paris Museum he was privileged to measure in great detail in July 2003. And sure enough, with a dorsal head length of 76 cm, a maximum skull width of 48 cm and a massive mandible of 98.3 cm this specimen gets the prize of biggest known C. porosus skull in the world; these three measurements exceed anything else on record for broad-snouted crocs. It was apparently killed in Cambodia in the early 1800s, but there are no other details.Giant Niles
The last lap of the “skullology tour” had to be Africa. Everyone has seen the spectacular footage of wildebeests and gazelles being snapped up like rats by huge Nile crocs but just how big are they? Local intelligence was that the largest Nile crocs were at Lake Chamo, a Rift Valley lake in southern Ethiopia. We used some fancy military issue, range-finding binoculars to get very accurate distances between us (and camera) and the crocs. Then, combined with an ordinary digital camera and a bit of Photoshop magic we got some accurate remote measurements of Nile crocs, some over 18 feet long—saltie size. This is how it’s done: do the range-finding and picture simultaneously, put the picture onto Photoshop where the pixel length of the croc is easily converted to millimeters, multiply the pixel length by the recorded distance of camera-to-croc in millimeters (ie how big it actually was on the camera sensor) and then divide by the focal length of the lens. This gives you a reasonably accurate length of the critter.We discovered a dusty little cubbyhole at the Arba Minch Crocodile Ranch near Chamo where skulls of crocs drowned in Nile perch nets were given their final rest. It was a bonanza of giant skulls and our excitement grew as we measured a dozen of the biggest. All we could think was “bloody hell, these are the biggest Nile croc skulls on record”. Our enthusiasm was obviously infectious, the Farm Manager, Assegid Gebre, got all the skulls cleaned up and the next time we visited he had them carefully mounted in glass cases. These are truly invaluable specimens, one measuring over 68 cm, the size of the Corrorboree Tavern saltie skull, the biggest we found in Australia. This Lake Chamo skull is the largest on record for C. niloticus!
After years of being convinced that salties are the biggest crocs, colleagues who knew of my interest, started sending in intriguing bits of information. One bit was the statistics of the skull of a monster American crocodile at the American Museum of Natural History (AMNH) in New York. At 73.5 cm it is a shade bigger than ‘Kalia’ the giant Orissa C. porosus skull.
Colin McCarthy with the largest crocodilian skull on record, British Museum
Photo courtesy: George Craig
But what really zapped us were skull sizes of the Malayan gharial (Tomistoma schlegelii): one at the British Museum measures 84 cm (this is presently the longest known crocodilian skull in existence), one at Munich Museum at 81.5 cm and another at the AMNH at 76.5 cm, overshadowing the other species. What the head to total length ratio is for this species is anyone’s guess. Our friend Uthen Youngprapakorn has a gang of living giant ‘Tommies’ at his Samut Prakarn Crocodile Farm in Bangkok; we just need to get his permission to jump in the enclosure and get some measurements (or figure out a way to do it remotely – with range finder technology). The third longest skull in the world is a gharial (Gavialis gangeticus) at Munich which is 77.3 cm, but again we don’t know how long the animal was or what the head to total length ratio for big gharial might be. Skull lengths are proportionally longer for these species compared with other crocs, and don’t necessarily translate to longest body length.Discussion
While we can now say with certainty that salties can reach lengths of 20 feet (6 metres) and above, it is also quite certain that the gharial, the Malayan gharial, the American croc and the Nile croc can reach over 20 feet in length. And we shouldn’t totally discount the Orinoco croc measured by A. von Humboldt’s assistant in 1800 which was purportedly 22 feet 3 inches (6.78 m) (Schmidt, 1944).
An interesting aside gleaned while spending an afternoon with paleo-croc master, Dr. Wann Langston Jr. at the University of Texas in Austin: while modern crocs seem to peak out at around 20 feet long, the big extinct mesoeucrocodilians like Deinosuchus, Sarcosuchus, Terminonaris seemed to have peaked at about 40 feet (and weighed up to 3,000 kg!) – wonder what their head to TL ratio is?.
This is an intriguing subject and hopefully this note will encourage colleagues out there to come up with some bigger skulls (or other solid evidence) than we’ve been able to find. It might also encourage some re-measuring, using a standard caliper, some creative mathematics to account for shrinkage and a more comprehensive table of crocodilian maximum sizes for all the species. We also need to take a cue from Webb and Messel (1978) where they suggest that it might make more sense to derive a relationship between volume of bone in the skull and total length rather than linear ratios which just don’t seem to work for the real big ones. And not to be ignored is the formula derived by John Thorbjarnarson and colleagues working with a large sample of Orinoco and American crocs. Their formula is: TL = hindfoot (longest toe with nail) length X 11.85 minus 12.97. The days of listening to the same old ‘bigger than the boat’ stories are over.
The below table lists the 30 or so biggest crocs/skulls we were able to locate and includes the very few examples of both Head Length and Total Length that we have been able to find for big crocs and also some of the wide ranging ratios that are driving us ‘skullduggers’ nuts. The unfortunate thing is that perhaps the genes favouring gigantism have been lost from the gene pool as a result of the selective killing of big crocs around the world. This is a good argument against the continued ‘safari’ harvests of the world’s remaining giant crocs and perhaps CSG can play a role in curbing this loss.
A number of colleagues generously contributed to this compilation of big croc information and we’d like to profusely thank Wayne King, the late Phil Hall, Ivan Ineich, Wann Langston, Peter Taylor, Paolo Piras, Gunther Koehler, Fred Glaw, Adam Britton, Charlie Manolis, Jack Cox, Mike Klemens, George Craig, Sudhakar Kar, Jerome Montague, Assegid Gebre, Allan Woodward, Ruth Elsey, John Thorbjarnarson, Ralf Sommerlad, Rich Fergusson, John Brueggen, Kent Vliet, Kaushik Deuti and others we may have omitted. Thanks also to the Icon Films crew for facilitating the croc measuring trip around the world and to African Parks colleagues who hosted Nik and I in Ethiopia. Janaki Lenin and Adam Britton kindly reviewed the manuscript.
- Banks, E. (1931). Some measurements of the estuary crocodile (C.porosus) from Sarawak. J.Bom. Nat. Hist. Soc., 34: 1086-8.
- Barbour, T. (1924). An historic crocodile skull. Copeia 126:16.
- Barbour, T. (1933). A large alligator skull. Copeia 133:43.
- Cory, C.B. (1896). Hunting and fishing in Florida. Estes and Lauriat, Boston, Massachusetts.
- Greer, A.E. (1974). On the maximum total length of the saltwater crocodile C. porosus. J. Herp. 8:378-81.
- Iordansky, N.N. (1973). The skull of the Crocodilia. In ‘Biology of the Reptilia’ (Eds. Gans and Parsons) Ch.5, pp. 201-62. (Academic Press, Inc, New York).
- Kar, S. (2006). Record of a large saltwater crocodile from Orissa, India, CSG/NL 25(3): 27.
- Kar, S. (2006). World’s largest crocodile skull? CSG/NL 25(4): 21-22.
- Manolis, C. (2006). Record of a large saltwater crocodile from the Northern Territory, Australia. CSG/NL 25(3): 27-28.
- Montague, J. Jerome. (1983). A new size record for the saltwater crocodile (C.porosus). Herp Review 14(2):36-37.
- Muller, Lorenz. (1927). Ergebnisse der Forschungsreisen Prof. E. Stromers in den Wusten Agyptens. 1. Beitrage zur Kenntnis der Krokodilier des agyptischen Tertiars. Verlag der Bayerischen Akademie der Wissenschaften. Munchen. Pp. 89-96.
- Piras, P. Unpublished Ph.D. Thesis: Theoretical morphology of fossil and recent crocodile skulls by means of 3 and 2-dimensional geometric morphometrics (pers comm. 2007).
- Schmidt, K.P. (1944). Crocodiles. Fauna 6:67-72.
- Webb, G.J.W. and Harry Messel. (1978). Morphometric Analysis of C. porosus from the North Coast of Arnhem Land, Northern Australia. Aust. J.Zool. 26: 1-27.
- Wermuth, H. (1964). Das Verhaltnis zwischen Kopf-, Rumpf- und Schwanzlange bei den rezenten Krokodilen. Senckenb. Biol. 45, 369-85.
- Woodward, Allan R., John H. White, and Stephen B. Linda, (1995). Maximum Size of the Alligator (Alligator mississippiensis). J. of Herpet. 29(4): 507-513
SOME LARGE CAPTIVE CROCS:
C.porosus – Jaws III at MCB, India – 16’10” (5.13m) DCL 56.3 RATIO: 1:9.1
C.porosus – Brutus, Cassius at Green Isle, Australia – 17 to 18 feet?
C.porosus – St.Augustine Alligator Farm, Florida – 15 feet six inches
C.acutus – Silver Springs, Florida – 16 feet?
C.p./C.s. hybrids at Samut Prakarn, Thailand – 18 to 20 feet ??
C.porosus – Moitaka, Port Moresby, PNG – 17 to 18 feet
C.porosus – Mainland Holdings croc farm, PNG – 17 to 18 feet
T.schlegilii – Samut Prakarn Croc Farm, Thailand – 17 to 18 feet
© Madras Crocodile Bank Trust