The world's largest modern crocodilian skull


Do you remember the photo - provided courtesy of Colin McHenry - showing a variety of crocodilian skulls? I published it in an article on the CEE Functional Anatomy meeting, and here it is again. The challenge was to try and identify the largest skull. Suggestions included Saltwater croc Crocodylus porosus, outsized American croc C. acutus or Slender-snouted croc Mecistops cataphractus, but it's none of those (for the resurrection of the genus Mecistops Gray, 1844 for cataphractus see McAiley et al. 2006). The monster skull is in fact that of a False gharial Tomistoma schlegelii. Yes, a False gharial. Holy shit. Hai-Ren actually got it right: well done you! At 84 cm long this skull might cause you to revise whatever preconceptions you had about a species with the name 'False gharial' (having said that, gharials proper ain't necessarily unimpressive... read on).

Thanks to Markus Bühler of Bestiarium, I've just learnt of Rom and Nik Whitaker's excellent article on gigantic crocs here at Here be dragons, a blog that I'll definitely be adding to the Tet Zoo sidebar. They provide much discussion of giant Salties, going over the famous 1980 Fly River (New Guinea) croc, the alleged Australian giants seen by Krys and Ron Pawlowski (they claimed to have shot a croc 8.6 m in length), and the various alleged giants from India [for previous discussion of giant size in Saltwater crocs see the comments at Tet Zoo POTD # 14]. They also discuss a gigantic specimen killed in Cambodia in the 1800s: its skull is preserved and, with a dorsal head length of 76 cm (see their article to understand how there is more than one way to measure a croc skull!) and with a mandibular length of 98.3 cm, is the biggest Saltie skull in existence. Then there are giant American crocs (one specimen, in the AMNH [= American Museum of Natural History, New York], is a true monster with a skull 73.5 cm long) and Nile crocs C. niloticus. And then there are the False gharials.


The NHM (= Natural History Museum, London) skull included in Colin's photo (Colin's homeboy Pete Edwards provides a scale) is the largest known modern crocodilian skull in existence. Here it is again, this time posing with sea snake guru Colin McCarthy. It isn't the only gigantic skull from this species: Rom and Nik Whitaker mention one at Munich which is 81.5 cm long, and one at the AMNH which is 76.5 cm long. Unfortunately it isn't entirely clear what the total lengths of these animals were, and it isn't yet clear what the skull length : total length ratio of this species is. It's well known that a fairly consistent 1 : 7 ratio has been proposed for crocodiles, but this seems not to work when applied to particularly large individuals: for full discussion of this you'll have to read the Here be dragons article.

Based on these giant skulls, we can be fairly confident that Tomistoma exceeds 6 m in total length and is one of the largest extant crocodilians. Most popular books on crocodilians state its maximum length as 4-4.5 m (e.g., Guggisberg 1972, Alderton 1991), so these authors evidently weren't aware of these giant skulls (Steel (1989) specifically referred to the giant NHM skull however, noting as a result that Tomistoma might attain a length of 5.5 m). In keeping with its sometimes gigantic size, it is probably not limited to a diet of fish 'and other small vertebrates' as some of the books say, and it is known to eat macaques at least. Incidentally, there are some fragmentary Siwalik Hills fossils in the NHM collection that look pretty huge, and were provisionally identified by Dino Frey as possibly belonging to Tomistoma. I have no idea whether these remains actually belong to Rhamphosuchus crassidens, a large species from the Miocene of the Siwalik Hills, identified variously as a tomistomine (false gharial) or a gavialoid (true gharial) by different authors. Head (2001) identified Rhamphosuchus as a tomistomine and noted that its length ranged from 8-11 m: not quite the 15-18 m previously mentioned by some (although 8-11 m is still plenty big enough I think).


Finally, let us note that the Gharial itself, Gavialis gangeticus, is not necessarily a small animal [adjacent image, from wikipedia, shows a captive False gharial]. A Gharial skull at Munich is 77.3 cm long (making it the third longest modern crocodilian skull), but again its total length was not recorded. Of course, there are tales of giants that were measured whole: an alleged 7 m specimen was shot on the Kosi River in 1924, a 6.6 m long individual on the Gogra River in 1920, and a 6.4 m animal was killed in the Cheko River in 1934. I have no idea whether these lengths were ever verified. It is well known that gharials have occasionally been found with jewellery in their stomachs, but this has been attributed to their possibly feeding on the remains of funerals, or even on picking up such objects for use as gastroliths. However, big gharials are not limited to a diet of small prey as they are alleged to sometimes take goats and feral dogs. There are a couple of authenticated attacks on humans: 55 year old Sankara Behera was attacked by one in 1979 at the Satkoshia Gorge Sanctuary (Bustard & Singh 1981). It grabbed his arm and he fell into the river; his son rescued him and he later recovered. A few other people have been bitten (Steel 1989), but these attacks mostly seem to have been motivated by territoriality or nest-defence.

Note how I cleverly avoided even mentioning the phylogenetic affinities of Tomistoma and Gavialis, easily the most controversial areas in crocodilian evolutionary biology.

Refs - -

Alderton, D. 1991. Crocodiles & Alligators of the World. Blandford, London.

Bustard, H. R. & Singh, L. A. K. 1981. Gharial attacks on man. Journal of Bombay Natural History Society 78, 610-611.

Guggisberg, C. A. W. 1972. Crocodiles: Their Natural History, Folklore and Conservation. David & Charles, Newton Abbot.

Head, J. J. 2001. Systematics and body size of the gigantic, enigmatic crocodyloid Rhamphosuchus crassidens, and the faunal history of Siwalik group (Miocene) crocodilians. Journal of Vertebrate Paleontology 21 (Supp. to No. 3), 59.

McAliley, L. R., Willis, R. E., Ray, D. A., White, P. S., Brochu, C. A. & Densmore, L. D. 2006. Are crocodiles really monophyletic? - Evidence for subdivisions from sequence and morphological data. Molecular Phylogenetics and Evolution 39, 16-32.

Steel, R. 1989. Crocodiles. Christopher Helm, London.


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I remember seeing a false gharial (if my memory serves me correctly that is) at the (frankly despicably ramshackle and poorly run) Jurong Reptile Park in Singapore. At the time I remember being surpised by how large and heavily built it was. I'd always kind of imagined (erroneously) the whole animal would be quite gracile based on the head but hell no.

I got it right? Hurray!

Just coincidentally, 2 weeks ago, I was sort of scrolling through the archives, wondering if you'd ever reveal the identities of the crocodilian skulls. I'm sure a lot of other people would love to find out the identity of all the skulls in that photograph.

I'm fairly familiar with Tomistoma, since it's been incorporated into quite a number of exhibits at the local zoo.

There's an underwater viewing gallert where you can watch Crocodylus porosus and Tomistoma schlegelii swimming around (the two species are separated). I'm not sure how big the false gharials in the zoo are, but they're definitely as large as the saltwater crocodiles.

I definitely won't be surprised if the largest Tomistoma or Gavialis take larger vertebrates, though I guess the ability of the jaws to withstand the stress of seizing struggling prey is an important factor.

When Gustave dies, I want his skull (hell, his whole skeleton!)... If the 20' (6.06 m) length estimate is correct, and the 1:8-1:9 skull:body length ratios hold for C. niloticus, its skull ought to be 68-75 cm long...

(For more on this giant Nile croc specimen, which apparently has been known to take down hippos, see here (especially right around 4:10 for a size comparison), here, and here.

[from Darren: delayed in the spam folder due to those links!]

Ed: I have no idea why my nickname in the previous comment links to Pharyngula.

tai haku: I've heard that the Jurong Reptile Park was a pretty dismal place, even at its peak. I haven't been there myself, but I'll check it out in the near future. That is, if it's still open...

The Singapore Zoo is a much better place to view Tomistoma, and looking at how many different exhibits have them on display (last time I was there, there were THREE separate exhibits featuring false gharial), they're probably breeding quite well.

I remember seeing that crocodile skull lineup while I was still a lurker. You never revealed the right answers? In that case, I'll have a go at guessing their identities too!

Here goes, from bottom to top:

-bottom three are all gharials (Gavialis) of different ages and genders;

-the robust one above the false gharial is a mugger Crocodylys palustris;

-the topmost one is a Crocodylys sp.; I'm guessing it's an Indo-Pacific species, as all the others seem to be from that region too. Young saltie perhaps?

I´ve seen some false gharials in Jong´s Crocodile farm in Kuching( well it is more than a farm, it is also a zoo and a conservation for the Gharials ) They also had an immense skull of a Saltie in their museum, I can send you a photo if you want, the crocodile has been measured at 6 meters but the skull looks a bit oversized for the body( I don´t want to claim that the croc was bigger than 6 meters, just that it had an oversized head)

I wonder if any zoo or reptile park will feed a young croc ad libitum and grows itself a true record-breaker Nile or saltwater.

You might also write about these Nile crocs isolated in Sahara. Pretty unusual from e.g. genetic drift point of view.

Jerzy: yes, the Saharan crocs are argued by some to be a distinct species that should be called Crocodylus suchus Geoffroy, 1807. See...

Schmitz, A., Mansfeld [sic: actually Mausfeld], P., Hekkala, E., Shine, T., Nickel, H., Amato, G. & Böhme, W. 2003. Molecular evidence for species level divergence in African Nile crocodiles Crocodylus niloticus (Laurenti, 1786). C. R. Palevol 2, 703-712.

Incidentally, these authors also argued for the distinction of Mecistops for the slender-snouted crocodile.

The wikipedia article on Tomistoma also has a picture of a skull, which to me does not look like Tomistoma at all... it actually looks more like (a female?) Gavialis gangeticus, look at the jugal, the postorbital bar, large supratemporal fenestra. Please, someone correct me if I'm wrong.

Darren said: "Note how I cleverly avoided even mentioning the phylogenetic affinities of Tomistoma and Gavialis"

Aww come on, that's the fun part!!

By Jorge Velez-Juarbe (not verified) on 30 Oct 2008 #permalink

I did notice how you cleverly avoided discussion of the real and false ghavial's phylogenetic affinities. This bothers me, because I'd really like to know what they are! Is the false ghavial really a sister species of the ghavial or a crocodile that converged on the ghavial? How far back do ghavial fossils go? I demand answers, sir! :-)

Wow, THATS best part! New, overlooked species, big & charismatic, extra-rare and with unusual ecology! How a heck such things are overlooked and no Steve Irvins, BBCs and WWFs are queuing for research and protection!!!???

Will look for that paper.

BTW - Tomistoma and Gavialus are close relatives. Another curious part is that all non-bird dinos were extinct but at least 5 croc lineages survived K/T: one ancestor of both gharials, of caimans, of Chinese alligator, separate of Missisipi alligator and of Crocodylus+Osteloaemus. Plus a question what about ancestor of mekosuchines and all other Tertiary forms?

Zach: Gavial fossil go back at least to the Latest Cretaceous with Eothoracosaurus mississippiensis (Campanian?-Maastrichtian, NA), Thoracosaurus neocesariensis (Maastrichtian-Paleocene, NA), and Ocepesuchus eoafricanus (Maastrichtian, AF). Also, most (if not all?!) phylogenetic analysis based on morphological characters will place Tomistoma (and allies) within Crocodyloidea, whereas Gavialis (and its extinct relatives) belongs in Gavialoidea. Molecular data places them as sister taxa.

These might offer some info on the old Gavials:
Brochu, C. A. 2004. A new Late Cretaceous gavialoid crocodylian from Eastern North American and the Phylogenetic Relationships of thoracosaurs. Journal of Vertebrate Paleontology 24(3):610-633.
Jouve, S., N. Bardet, N.-E. Jalil, X. Pereda Suberbiola, B. Bouya and M. Amaghzaz. 2008. The oldest African crocodylian: phylogeny, paleobiogeography, and differential survivorship of marine reptiles through the Cretaceous-Tertiary boundary. Journal of Vertebrate Paleontology 28(2):409-421.

This one offers info on relationships and the controversy:
Brochu, C. A. 2003. Phylogenetic approaches toward crocodylian history. Annual Review of Earth and Planetary Sciences 31:357-397.

By Jorge Velez-Juarbe (not verified) on 30 Oct 2008 #permalink

On the affinities of tomistomines see also...

Gatesy, J., Amato, G., Norell, M., DeSalle, R. & Hayashi, C. 2003. Combined support for wholesale taxic atavism in gavialine crocodylians. Systematic Biology 52, 403-422.

- . & Amato, G. 2008. The rapid accumulation of consistent molecular support for intergeneric crocodylian relationships. Molecular Phylogenetics and Evolution 48, 1232-1237.

Janke, A., Gullberg, A., Hughes, S., Aggarwal, R. K. & Arnason, U. 2005. Mitogenomic analyses place the gharial (Gavialis gangeticus) on the crocodile tree and provide pre-K/T divergence times for most crocodilians. Journal of Molecular Evolution 61, 620-626.

See also Jorge et al.'s 2007 paper on the Puerto Rican gharial Aktiogavialis, available for free here. Nice to see you here Jorge, thanks for your comments!

Oh yeah, and...

The wikipedia article on Tomistoma also has a picture of a skull, which to me does not look like Tomistoma at all... it actually looks more like (a female?) Gavialis gangeticus, look at the jugal, the postorbital bar, large supratemporal fenestra. Please, someone correct me if I'm wrong.

I agree; that's a Gavialis skull.

Is there any change in habitat when false gharila get bigger? I've heard of the largest saltie specimens mainly living in the sea, am I misinformed?

By Tim Morris (not verified) on 31 Oct 2008 #permalink

Hey, hi Darren! Nice to see that the Aktiogavialis paper is available for free! Gavials are pretty interesting animals, even more if you look at their paleobiogeographic distribution!!

By Jorge Velez-Juarbe (not verified) on 31 Oct 2008 #permalink

Another curious part is that all non-bird dinos were extinct but at least 5 croc lineages survived K/T: one ancestor of both gharials, of caimans, of Chinese alligator, separate of Missisipi alligator and of Crocodylus+Osteloaemus.

Separate Cretaceous ancestry for Alligator sinensis and Alligator mississippiensis?!? Despite the nice Miocene record of Alligator? You must have confused something.

By David Marjanović (not verified) on 31 Oct 2008 #permalink

Gavials are pretty interesting animals, even more if you look at their paleobiogeographic distribution!!

Yes, gharials are too cool - especially the giant, relatively recent-ish marine ones. Must blog about them some day. Big love for Piscogavialis.

Incidentally, the skulls in Colin's photo are (top to bottom), 'normal' Crocodylus porosus, gigantic example of same, gigantic Tomistoma, big Gavialis, juvenile Gavialis, and 'normal' Tomistoma. Thanks to Colin for confirming this.

It is in DNA, I think in one of above papers. Yes, its incredible.

I few months ago I bought my first crocodilian skull off ebay. I remember thinking how big it was compared to my alligator heads (the kind that still have all the skin on them with the mouth open, something commonly found here in Louisiana convenience stores).

I don't think it's very big anymore.

It is in DNA, I think in one of above papers. Yes, its incredible.

Then it's miscalibrated and best forgotten. :-|

By David Marjanović (not verified) on 31 Oct 2008 #permalink

Huh? I guess I misinterpreted the initial question. I thought it was asked what the largest skull in the photo was. I assumed it to be the second one from the top (the gigantic example of C.porosus). Tomistoma had the longer skull, but it doesn't look quite as massive (i.e. big) as the saltie skull.

There is a paper which states that caimans and alligators diverged in the Late Cretaceous about 80 mya, while the two extant Alligator species diverged in the late Paleocene, about 50.9 mya.

Wu, X. Wang, Y. Zhou, K. Zhu, W. Nie, J. Wang, C. Complete mitochondrial DNA sequence of Chinese alligator Alligator sinensis and phylogeny of crocodiles. Chinese Science Bulletin, 2003, 48(19): 2050-2054.

Besides the gavialoids, alligatoroids and crocodyloids, let's not forget that the sebecids and dyrosaurids also survived the K-T mass extinction, while among the Crocodylia, Borealosuchus and Pristichampsus are known from the Paleocene and Eocene.

Tim Morris: The false gharial appears to be a specialist of peat swamp and freshwater swamp forests.

Stuebing, R.B.; Bezuijen, M.R.; Auliya, M. & Voris, H.K. 2006. The current and historic distribution of Tomistoma schlegelii (The False Gharial) (MÜLLER 1838) (Crocodylia, Reptilia). Raffles Bull. Zool. 54 (1): 181-197 (available here)

Late Paleocene seems very likely for the separation of the two Alligator species. The PETM (Paleocene-Eocene Thermal Maximum) would be just about the only time that an Alligator might cross Beringia (or Greenland/Spitzbergen).

As for several croc lineages surviving the K/T extinction, this is not so surprising since freshwater taxa generally seem to have survived much better than either marine or terrestrial forms. Too bad there weren't any otter dinosaurs or beaver dinosaurs.

About the food habits of gharials a friend of mine got rather badly bitten by a gharial once. This was a quite small animal, and about as harmless as any crocodile ever is. However my friend happened to touch the side of its snout, and apparently you should never do this, since it will snap reflexively at whatever touches it.

By Tommy Tyrberg (not verified) on 31 Oct 2008 #permalink

In the herpetology exhibition of the Natural History Museum at Vienna are two very large indian gharials, which are about 5m long. You can see a phot of the male here:
When I was at the zoological institute of Hamburg some months ago, I saw also some really big stuffed crocs. There was also a huge skull of a Mississippi alligator. I have to say that I was really shocked when I saw it. It was really monstrous, and extremely wide and robust. They look even much more robust when the mandible is still present. At the same day I also visited the collection of the paleontological museum of Hamburg, where a replica of the skull of Asiatosuchus was exhibited. Okay, it was not that long, but its sheer bulkyness was really impressive.
When you think about how huge those giant specimens of C. porosus were, you could easily imagine that such a monster could even drag a water buffalo, a smaller rhino or subadult elephant into the water. At 7m they would weigh more than 1500kg.

Late Paleocene seems very likely for the separation of the two Alligator species. The PETM (Paleocene-Eocene Thermal Maximum) would be just about the only time that an Alligator might cross Beringia (or Greenland/Spitzbergen).

The early Miocene was warm enough, judging from the current distribution of the Mississippi gator. And, once again, Alligatoroidea has a great fossil record that can't simply be ignored. There are several great Brochu papers on it.

By David Marjanović (not verified) on 31 Oct 2008 #permalink

If we talk about giant tomistomines, we should also not forget the giant Melitosaurus champsoides from Malta, which was about twice as large as normal false gharials.

A recently described South American gryposuchine gavialoid, Gryposuchus croizati, from the Late Miocene of Venezuela, has a skull length of about 1.50 meters long with an estimated total body length of 10 meters (Riff & Aguilera, 2008). They compare the total body length with Sarcosuchus imperator (11.5 m), Deinosuchus (9.1 m), Rhamposuchus crassidens (~15 m), Purrusaurus mirandai (8.2-11.5 m) and Purrusaurus brasiliensis (12 m). So, it seems that the tomistomine R. crassidens is the largest overall, and G. croizati the largest within gavialoids.

Riff, D. and O. A. Aguilera. 2008. The world's largest gharials Gryposuchus: description of G. croizati n. sp. (Crocodylia, Gavialidae) from the Upper Miocene Urumaco Formation, Venezuela. Pal�ontologische Zeitschrift 82(2)-178-195.

By Jorge Velez-Juarbe (not verified) on 08 Nov 2008 #permalink

It seems like giant size has evolved independently lots of times in crocodilians (the Gryposuchus gavials mentioned above, Deinosuchus is an alligator, Sarcosuchus a crocodile, Purrusaurus a caiman, right?)

How different is the body structure of fossil giant crocodiles - did they have special weight-bearing adaptations? If not, could false gharials or estuarine crocodiles theoretically be bred to Purrusaurus-size? (not that it would be advantageous, but would it work?)

By William Miller (not verified) on 08 Nov 2008 #permalink

Yes, giant size has evolved independently within crocs quite a number of times.

In terms of their body structure, Gryposuchus croizati is only known from skull. Purussaurus mirandai is known from skulls, as well as postcranial material, but they're not described, so I'm guessing there's nothing special about them?! For Sarcosuchus imperator there's also postcranial material, but nothing is mentioned about having any special adaptation for its size.

Aguilera, O. A., D. Riff & J. Bocquetin-Villanueva. 2006. A new giant Purussaurus (Crocodyliformes, Alligatoridae) from the Upper Miocene Urumaco Formation, Venezuela. Journal of Systematic Palaeontology 4(3):221-232.

Sereno, P. C., H. C. E. Larsson, C. A. Sidor & B. Gado. 2001. The giant crocodyliform Sarcosuchus from the Cretaceous of Africa. Science 294:1516-1519.

By Jorge Velez-Juarbe (not verified) on 09 Nov 2008 #permalink

There's actually a skull of a saltwater crocodile that was given to harvard that is 5feet 6inches long.I even found a picture of the skull it is very easy to find.

Harvard University is home to a giant saltwater croc skull that was supposed to belong to an individual 8.2 m long (27 ft). It was shot in 1823 by Paul De La Gironnière on Luzon in the Philippines. However, the skull is not 1.7 m long (5 ft 6 in), but 64.77 cm. This suggests a total length of 6 m.

Is there really another specimen more than twice as large? I don't think so.

I wonder if this is a case of confusion somewhere along the line between inches and centimetres, as 65 inches is 5ft 5 in?

By Mark Evans (not verified) on 23 Jun 2009 #permalink

Good call Mark, you could well be right. This sort of thing seems to happen all the time. I would soooo love it if there were a modern croc with a skull 1.7 m long!

It could be a differn't skull from a differnen't museum but I assure you that when I went on this Harvard site it said the length of the skull and the story and frankly I heard that this crocodile skull came from a crocodile killed somewhere else and it is said that it ate horse and when it was killed the found the body of the horse in seven pieces. Oh and I am talking about a way differnen't skull.

By Anton Hinds (not verified) on 06 Sep 2009 #permalink

Oh guys I am so sorry it turns out that I made a mistake about the skull being 5 feet 6inches. Although it said that it was that long in the article a crocodile with a head that big would be prehistoric and I mean Deinosuchus prehistoric and it would look to weird any way so my bad. It is probably the same skull you mentioned or it is much smaller like maybe 3 feet long so my bad.

By Anton Hinds (not verified) on 10 Oct 2009 #permalink

The largest saltwater crocodile skull in the world is in the Paris Museum and if I could show you a picture I would but it was killed in Cambodia in the early 1800s and that is all that is known.

By Anton Hinds (not verified) on 10 Mar 2010 #permalink

i have seen a false gharial with a skull length of 80cms from the back of lower jaws to front of nose . a saltwater croc 83cms measured the same. a male indian gharial 87cm and a female indian gharial 80 cm what sizes would the living crocs have been

Although I find most accounts of saltwater crocodiles as long as 33 feet as exggagerations there is one account that when you really think about it has some validity to it here is the account:The local Seluka tribe believed that it was "The Father of the Devil" and threw silver coins into the water to appease it, bringing to mind the dragon hordes of legend.

Investigating, Montgomery found the beast in question hauled out on to a sandbank. The crocodile filled the whole bank and had the end of its tail in the water. Wisely deciding to leave the monster well alone Montgomery retreated. Returning later he found that the sand bank on which the creature had been basking was 9 metres (30 feet) across indicating that the creature must have been in excess of ten metres (33 feet) in length.

By Anton Hinds (not verified) on 17 Aug 2010 #permalink