With six years of phd work on theropod dinosaurs behind him, Darren Naish mostly spends long hours in the library, hunched over his laptop. But he gets out sometimes, and picks up litter and pursues exotic lizards across the British countryside, aiming all the while to publish his technical work on obscure Cretaceous dinosaurs. He also messes around with pterosaurs, swimming giraffes, British big cats and stuff like that. He has given up on the stupid idea of being a dedicated academic and ekes out a living as a technical consultant, editor and author. He can be contacted intermittently at eotyrannus (at) gmail dot com. For more biographical info go 
You've probably seen - presumably on TV - Nile crocs Crocodylus niloticus interacting with Common hippos Hippopotamus amphibius (if you've seen it in real life, lucky you). By and large the two seem to keep apart. Having said that, there are certainly photos of the two sharing the same sandbanks. And then there are those instances of hippos scaring crocs away from carcasses, the weird reports of hippos mouthing and chewing the backs and tails of resting crocodiles, and those cases where crocodiles have been seen to walk or run across hippos' backs.
What can certainly be said to be the most remarkable croc-hippo encounter yet reported was photographed by Czech wildlife photographer Václav Šilha last year, and yesterday they were featured in various national newspapers. Here's the best photo (in my opinion: you may already have seen it November's BBC Wildlife magazine).
Šilha reports that the crocodile had tried to attack a calf, but that the entire herd rallied against it and formed a defensive circle (I'm not sure that circle is the right word: wouldn't 'scrum' or 'wall' be more like it? Look at the photos). The crocodile then tried to escape by crossing over the backs of the hippos [as shown in the photo below, taken seconds prior to the one shown above]. They reacted aggressively and several individuals bit the croc repeatedly. It disappeared under the water and wasn't seen again. Šilha is pretty sure it was dead, but it's not possible to be sure about this from the photos (not that I'm doubting him). The event happened on the Grumeti River in Serengeti National Park, Tanzania.
The literature (e.g., Pooley & Ross 1989) says that aggressive encounters between Nile crocodiles and hippos have been recorded before: it's typically stated that hippos have been seen killing crocodiles when defending their calves. Nevertheless, I'm not aware of any previous such cases being captured on film. Hats off to Šilha, then, for recording such an extraordinary event. We often see images of remarkable fights, deaths and other events in the news media these days, and - if the images are good enough - such events quickly become widely reported online. Is anyone aware of such a case ever being reported in the technical literature, and do people agree with me that there's a need for such cases to be put on 'official' record? Just a thought.
Thanks to MPT for the heads-up. For previous Tet Zoo articles on unusual animal conflicts see...
- Animal deathmatch: rhino vs croc, hippo vs shark.... leopard vs small passerine??
- Leopard vs crocodile (better late than never)
- PVP : Predator vs Predator
And for more on crocodilians and how neat they are see...
- Chito and Pocho, frolicking in the water
- Enough mammals for the time being: crocodiles on Inside Nature's Giants (part III)
- Alligators vs melons: the final battle
- RoboCroc
- The world's largest modern crocodilian skull
- Do crocodilians (sometimes) feed their young?
- Alligators eat fruit
Ref - -
Pooley, A. C. & Ross, C. A. 1989. Mortality and predators. In Ross, C. A. (consulting ed) Crocodiles and Alligators. Merehurst Press (London), pp. 92-101.
Comments
Slightly unrelated, but if you haven't seen it a pygmy hippo was recently shot here in Australia in the Northern Territory. http://www.ntnews.com.au/article/2009/11/16/101241_ntnews.html
Posted by: Stephen | November 17, 2009 5:22 AM
Thanks Stephen, what an extraordinary story. For those who haven't clicked on the link yet, the hippo was killed by accident during a pig-shoot and had been living in the wild for about five years after its escape or release from a (now closed) wildlife park. As is noted in a related article, how many other big escaped exotics might be lurking, unknown to anyone, in the area?
Also in hippos news, there were the recent photos of the guy in Uganda running for his life: here (be sure to look at all three pics).
Posted by: Darren Naish | November 17, 2009 6:03 AM
According to this site, it's either a 'bloat', a 'crash', a 'herd', a 'pod', a 'school', or a 'thunder' or of hippos. (And it would be a 'bask', a 'congregation', a 'float', or a 'nest' of crocodiles.)
Yes! Absolutely. It may be anecdotal but it's still data.
Stephen:
Un-frikkin-believable!
Posted by: Dartian | November 17, 2009 8:46 AM
Hi Dartian. I wasn't looking for the 'correct' plural for hippos; rather, I'm not sure that the hippos really did form a defensive circle as stated. Judging from the photos, they've just massed together.
As for anecdotes being data, I find your statement interesting in view of Charles Paxton's recent talk at the sea monster conference. Check out this excerpt from my (yet to be published) write-up of the meeting...
In other words, anecdotes can be very important.
Posted by: Darren Naish | November 17, 2009 9:16 AM
Pygmy hippos in Australia? Reminds me to the hippos in Colombia which even reproduced in the wild.
I remember that there is an ancient egypt wall painting or carving (have to check from where and which time), which shows a hunt on the nile. As far as I remember, there is also a hippo with a big croc between its jaws, very similar to the photo on the top.
Posted by: Sordes | November 17, 2009 9:28 AM
Just for the record, that's a nice pair of caniniform teeth in the maxillae of that croc. Another in the premaxillae, and two more in the dentaries.
BTW, Sereno gave a talk here 2 weeks ago where he briefly showed a head reconstruction of what must be the "boar croc". It's a fantastic beast. Vaguely reminiscent of the temnospondyl Dendrerpeton, only more badass.
Posted by: David Marjanović | November 17, 2009 9:33 AM
In the "animal deathmatch" series:
http://www.youtube.com/watch?v=JrGbh-6cAZA
Posted by: Jerzy | November 17, 2009 1:23 PM
TEH HIPPOO IT BEH EETIN MEH!
Posted by: Tim Morris | November 17, 2009 4:36 PM
I seem to recall on one of the discovery/nat geo shows about crocs someone was catching a large nile croc (it may even have been a quest for Gustav) when the croc they had noosed and were in the process of catching at night was killed stone dead by something under water (or undercover of darkness). A large wound attributed to a hippo tooth (tusk?) was found in the middle of it. Can't remember which show though.
Posted by: tai haku | November 17, 2009 4:50 PM
Huh! I always thought hippos to be docile creatures!
Although...admittedly, when I read the post title on my blogroll, for some reason I though Hippos were carniverous...or perhaps omniverous, but I see now that the simple, yet classic "predator killed by mama while protecting her baby" routine. lol! Poor Crocodylus nitolicus. :(
Posted by: Raptor Lewis | November 17, 2009 5:35 PM
Surely you know about the Animal Kingdom Kumite:
http://www.hackcanada.com/canadian/zines/spacemoose/kumate.gif
Posted by: lll | November 17, 2009 9:26 PM
it was not Australian pygmy hippo! It was a baby Diprotodon! ;-)
Posted by: Jerzy | November 17, 2009 9:32 PM
I remember an old film with hippos congregating in a drying waterhole and giant catfsh crawling on their backs like that croc.
Posted by: Jerzy | November 17, 2009 9:34 PM
Amazing photo, but not as amazing as the image in my head when I first saw the headline. I had read "hippos" as "hippies." Now *that* would be a picture! ;)
Posted by: Joseph | November 17, 2009 10:04 PM
The ones that went wild in Colombia belonged to Pablo Escobar.
Pablo had a menagerie at his estate, and when he got gunned down, his creatures were sold off.
Except for four of his hippos, which went wild on the estate.
There are now over 20 of them, and a bull and cow escaped into the Magdalena River system. They produced a calf and were seen all over the Magdalena Valley. They were last seen 65 miles form Pablo's estate, where the Colombia government shot the bull.
The last I heard, the owners of Escobar's estate were trying to give the hippos to a zoo, simply because they were a pain in the rump and a major liability. That estate is now open to the public as a tourist attraction!
I heard a zoo was interested in them, but thus, far I can't find any information on them.
Posted by: retrieverman | November 18, 2009 12:23 AM
Darren:
I quite agree. Provided, of course, that constructive source criticism is applied.
I'm not aware of any such reports in the peer-reviewed literature, but I found this mention in Hugh B. Cott's book Looking at Animals: A Zoologist in Africa (Collins, London, 1975). When he's discussing the interspecific relations between crocodiles and hippos he writes:
Cott's South African reference could perhaps be James Stevenson-Hamilton's Wild Life in South Africa (Cassell, London, 1947), where supposedly an incident where a hippo kills a crocodile is described. But I haven't seen Stevenson-Hamilton's book myself, so I don't know what exactly it says. Any Tet Zoo readers who have access to that book?
Posted by: Dartian | November 18, 2009 2:29 AM
(Btw, Paraa is located in the Murchison Falls National Park, Uganda.)
Posted by: Dartian | November 18, 2009 2:34 AM
According to this site, it's either a 'bloat', a 'crash', a 'herd', a 'pod', a 'school', or a 'thunder' or of hippos. (And it would be a 'bask', a 'congregation', a 'float', or a 'nest' of crocodiles.)
Interesting(ish). Herd is the default collective noun for large "ungulates" sensu lato, but I've only ever seen pod and school used for cetaceans (and fish) before. I know hippos are this week's closest living relatives to the cetacea, but presumably this is simply a striking coincidence?
I think I prefer "bloat".
Posted by: chris y | November 18, 2009 6:46 AM
I'm quite proud of being able to say I was chased by a hippo. Proud NOW - at the time I was terrified. I disturbed one that was grazing on a lawn (at night) between some houses by a river in eastern South Africa. Walked round the corner almost straight into it. It ran straight at me and I lit out into some thorn trees and somehow got up one (I don't remember climbing - I sort of floated up one in half a second). I looked down to see it directly below, and then it turned and ran back to the reeds. In my memory the brief moment that I saw it running at me before I turned and fled it seemed to have just the same gait as walking but faster (a lot faster). This is like elephants of course that don't 'run', just 'walk' helluva fast. Is this true of hippos as well? I know that rhinos also look a bit like that when they go fast too but they also change their gait when they go really fast. True or was it just adrenalin-influenced thinking?
Posted by: Bill | November 18, 2009 10:15 AM
Hippos are one of the very rare few digitigrade non-graviportal animals known that are incapable of a suspended stage run. Just like humans are one of the very rare few graviportal plantigrade mammals that _can_ run with a suspended stage. Rhinos are built much like hippos but all species are capable of a suspended stage, in fact, they can all gallop IIRC.
Posted by: Raymond | November 18, 2009 12:29 PM
No scientist present in this video of hippo and croc but the behavior is shown.
http://www.youtube.com/watch?v=jDL83LwfyzA
Posted by: david | November 18, 2009 3:10 PM
Looks like the NT pygmy hippo is heading to the NT Museum.
On the subject of crocs, some good news re C. siamensis:
http://media.smh.com.au/world/world-news/siamese-crocodiles-not-extinct-869503.html?&from=strap
Posted by: Colin McHenry | November 18, 2009 6:52 PM
Yet more amazing pictures.
Comment 7 Jerzy - You tube woodpecker v snake film astonishing.
Posted by: rose | November 19, 2009 8:12 AM
In other news, did you see Paul Sereno discovered a crocoduck? Guess that'll shut Kirk Cameron up.
Posted by: omphaloskepsis | November 19, 2009 3:45 PM
The new discoveries are awesome, congrats to the authors (Sereno and Larsson: free pdf here). Minor point: duck-billed Anatosuchus is not among the new taxa, it was named in 2003.
Posted by: Darren Naish | November 19, 2009 4:48 PM
The money shots in Sereno and Larsson are on page 99.
Posted by: Nathan Myers | November 19, 2009 6:00 PM
Thanks for posting this, this would help me overcome my fear of crocs
Posted by: movers in Washington | November 20, 2009 1:00 AM
When I hear "Crocodiles interacting with hippopotamus," I can't help but think of Disney's Fantasia.
Posted by: Andy | November 23, 2009 2:13 AM