Posts Tagged 'behaviour'

Project Daspletosaurus 2013

finalwide-on-white

I’m sure a goodly number of readers are already aware of this as I’ve been tweeting and facebooking it quite a lot, but I have a science kick-starter project running on the Microryza site. It sounds almost too contrived to be honest, but it’s a project aimed at looking at possible cannibalism in Daspletosaurus based on material Darren Tanke has worked on at the Tyrrell.

Obviously Darren and I have form when it come to tyrannosaurs, both with our own research interests and in particular with the Gorgosaurus preparation project. Here though it’s a skull of Daspletosaurus with bite marks attributable from another large tyrannosaurine. I’m looking for funding to get me out to Alberta and check out this and related material and work to write this all up and hopefully learn something about tyrannosaur behaviour and ecology.

Daspleto rt lat edited skull

I’ll skimp on the details here because it’s all up on the Microryza site, so do follow this link and take a look. More specifically, if you can spare a small amount towards the total, it would be very much appreciated and do please blog and tweet this – the model only really works if people know about it and are intrigued or excited so spreading the wrod is very important (and free!). Obviously I’ll be blogging the project and putting as much information out as I am able, so I hope to make this as open as I can and get the audience involved.

My thanks to Microryza for supporting this, and to David Orr for the fantastic logo up top and Matt van Rooijen for help with the project video (featuring much Matt artwork).

 

 

Fighting zebras

On my recent trip to Marwell, I and my colleagues were treated to quite a number of interesting animal behaviours. One of these was a pair of zebras having quite a serious disagreement. The encounter lasted a good few minutes and with lots of kicking, biting and general jostling. All of us burned off plenty of frames on the cameras and we come out with some good shots, and here are the best of mine.

As usual though, there’s a little scope for me to mention dinosaurs and palaeobehaviour. While obviously some animals were better equipped than others to fight, pretty much all species engage in some form of intraspecific combat at some point. You don’t have to have horns or tusks or spikes to inflict some serious injuries on your opponent and while a zebra may be rather less well equipped to deal out damage than say a buffalo, that doesn’t mean it can’t injure or kill another zebra. Similarly, while I imagine the primary reaction of any hadrosaur to a serious predator would be to flee, I’m sure that a pair of edmontosaurs with enough to fight over would have bitten and stomped as far as possible and fights would doubtless have got nasty – it wouldn’t just be the ceratopsians that would have tried to defeat one another.

Incidentally, I can’t help suspect that ‘the fighting zebras’ is the name of some US college basketball team or some long forgotten infantry company. And if it isn’t, it really should be.

Velociraptor scavenging an azhdarchid pterosaur

Image courtesy of, and copyright to Brett Booth.

So yesterday at short notice I rushed up this teaser post which seemed to do the trick, and now I’ve got a bit more time on my hands, I can start putting down a proper post on the subject. Yep, I have a new paper out and this time featuring dromaeosaurs and pterosaurs. Long time readers will remember that almost exactly 2 years ago I had another paper out on dromaeosaur scavenging featuring shed teeth and bite marks on some Protoceratops material. Coupled with the famous fighting dinosaurs specimen we have pretty good evidence for dromaeosaurs, and specifically Velociraptor for feeding on this dinosaur. The record of dromaeosaur predation and feeding is actually pretty good compared to other theropods groups and there is also an isolated pterosaur wing bone from Canada with shed dromaeosaur teeth and bite marks.

This ‘new’ specimen marks the first record of gut contents for Velociraptor and the first record of a pterosaur bone as gut content in a theropod. (The ‘new’ is becuase this specimen was actually found in the 1990s, but has yet to be described, though I’m told there’s a photo of it in Luis Chiappe’s recent birds book). Thus we do have rather exceptional evidence for a Velociraptor chowing down on an azhdarchid.

Velociraptor specimen with a pterosaur bone as gut content (black arrows). From Hone et al., 2012

And here it is, well part of it. The Velociraptor in question was remarkably well preserved and complete which allowed the preparation of it with the chest cavity as a single articulated piece with the vertebrae, sternum, ribs, gastralia and even uncinate processes all intact and in their original positions. The bones are really well preserved and much of the material has been prepared free of the matrix entirely. One obviously example is the skull which, bizarrely, is on display in Barcelona so at least some reader might have already seen that, though sadly I haven’t and had to rely on some superb photos kindly sent by Fabio Dalla Vecchia. It’s hard to show the bone off properly what with the whole ribcage in the way (which is, incidentally, a broken ribcage, one of the ribs took a huge battering and shows a healed break – white arrow in the above picture). S you’ll be delighted to know there are also some close-ups in the paper like this one (below) and even some CT scans in the supplementary data.

Close up of the bone. From Hone et al., 2012

As you can see the bone is incredibly thin-walled which is the major reason that it’s inferred to be an azhdarcid pterosaur, though their presence in the Late Cretaceous, including a related formation, and the general absence of other pterosaurs in the Late Cretaceous helps support this identity. Given what is around and the thinness of the bones, it’s pretty unambiguous as indeed is the identification of the dromaeosaur as Velociraptor given that we have basically the whole thing. In short, this is about as convincing a case as one could make that a Velociraptor had eaten an azhdarhid. But was it really scavenging? Well that and other issues I’ll be talking about tomorrow, as there’s quite a lot more to say on this. Stay tuned.

Finally, my thanks to Brett Booth for more awesome artwork for me to use, and you can see more of this and my interview with him on his dinosaurs here.

Hone, D.W.E., Tsuhiji, T., Watabe, M. & Tsogbataar, K. Pterosaurs as a food source for small dromaeosaurs. Palaeogeography, Palaeoclimatology, Palaeoecology, in press. Horrible uncorrect proof and behind a paywall, but the abstract, figures and other bits are visible to all.

Triceratops vs Tyrannosaurus

Perhaps the most obvious mainstay of dinosaurs in art and culture is the stand-off between the giant, fanged Tyrannosaurs and the horned and frilled Triceratops. It’s pretty much a cliché for dinosaurs that these two will fight each other when together and that the predator is always after his well-defended prey.

Obviously, I generally don’t think that tyrannosaurs (or most theropods for that matter) tackled healthy adult prey when there was a great selection of tasty, small, largely defenseless and naïve juveniles around. Now that makes sense at the best of times (and is borne out by what modern predators do, not to mention the inferences about dinosaurs) but a photo like this really makes you wonder.

OK, rexy is lying down (and it’s not the biggest specimen), but the difference in size is quite obvious. Triceratops is really, really big. Even in comparison to the ‘king’ it’s a huge animal with a massive skull, long horns, and a big body and a lot of weight behind it. There’s reason lions don’t generally tackle adult buffalo and won’t go near rhinos and that’s because they are too likely to get stompted, gored, or generally injured. This is a big and intimidating animal, and while eyeballing skeletons is not the best way of assessing complex behaviours, I do find it hard to believe that this was a normal prey choice for a tyrannosaur.

Marabou stork couchant

 

A trip to Beijing inevitably means a trip to the zoo given that it is opposite the IVPP and costs only a couple of dollars to get in. This time I was on a mission with Corwin Sullivan to look at a variety of birds for some anatomical and behavioural things we are interested in. One thing that did stand out by not standing up was the marabou storks. These are normally quite happy to stand as most wading a long-legged birds do – one one of both legs with the neck rather hunched up to the body (standing marabou above, obviously). However, three of them had adopted a sitting position on the ground far more like a chicken or duck than anything else.

Colour me ignorant, but I’ve never seen this in a bird of this size or this kind and while I can imagine them doing it on a nest perhaps they really seemed to just be resting. Is this common and I’ve simply missed it, or is this genuinely a bit odd?

 

Multifunctionality

I have complained before (who? me? complain?) about the common journalistic fallacy that proof of X is not proof against Y. All proving X does is show that X is true, not that Y is false. However, it’s easy to see how this comes about – many ‘obvious’ anatomical features certain seem to have, or are famous for having, just a single function. Deer fight with their antlers, peacocks display with their tails and so on. However, even some supposedly monofunctional features can have more functions, if more minor ones – the antlers of deer and horns over various bovids are used for fighting off predators as well as rivals, but also act as rather minor heat-loss features. Sure, it’s pretty minor, but it is a function that they perform, and may even be selected for.

Some features however can have a great many functions and all of them may be important. Both the tusks and trunk of an elephant can be used for all manner of things – fighting, signalling, collecting food, manipulating the environment and others. It’s not only hard to say which of these is the most important now, but which (if any) may have been the original driving force behind it’s selection is very hard to tease out. Thus making explicit statements about other functions and the selection pressures behind them is a very risky thing to be do without good evidence. Sorting this out properly requires, as far as possible, testing individual hypotheses about function in isolation and rejecting or accepting them based on the available data.

This should be quite obvious, and yet inevitably in the media (and sadly, on quite a few occasions in the literature) this simple error is repeated. Single functions are tested and found to be a use of a feature but then this is then incorrectly extended to be assumed to be the sole or primary function. Watch out for these, they can be very misleading and it is an exceptionally easy trap to fall into.

Thanks to Rachel Kilby for the photo.

Extrapolating behaviours – picking the right analogue

Palaeobehaviour is perhaps the hardest area of research in palaeontology, and is certainly one with the most speculation involved. If you know where and how to look, there are all kinds of evidence available in the ichnological and osteological record but of course the real issue is interpreting it correctly and tying the evidence to the right taxon in the right way. Sure you have a nice hadrosaur femur with some tooth marks, but from what? A theropod or a crocodile? And did it kill it, or just find it already dead? Was there only one animal feeding or more? Even with a good fossil record to let you know what other animals were out there, and how many, and what the environment was like, there are generally so many possibilities it can be very hard to make even vaguely reasonable generalisations about behaviour based on a single specimen or even a good collection.
Continue reading ‘Extrapolating behaviours – picking the right analogue’

Pachycephalosaur head butting

Pachy fight52Despite my interests in dinosaur behaviour I have rather managed to avoid the question of pachycephalosaurs so far and with a couple of nice photos on cue it seemed a good time to discuss this at least superficially. I don’t think this clade has actually even been mentioned here at any point so this is longer overdue.

Since I try to cover even the basics of archosaur palaeontology on here I should probably give a bit of background to these bone heads (as they are occasionally know – the literal translation of the name being thick headed reptiles). Pachycephalosaurs are a group of ornithischian dinosaurs closely allied to the ceratopsians (the horned dinosaurs) and with them make up the large and important clade the Marginocephalae. They were herbivorous bipeds that only spanned a relatively small range of sizes from small to medium (compared to many of their relatives) with the largest genus, Pachycephalosaurus, being up to around 5 m long.

Pachy2Obviously their most prominent characteristic is the massively thickened skull roof and the occasional fringe of spines and knobs that run around the crown of the skull. What these were actually used for has long been contested with the most obvious suggestion being that these were used to fight with, either with each other or to attack other animals (like predators). Evidence has gone backwards and forwards over this with papers saying the head could not have absorbed impacts of fighting, or could have done, that they would clash heads or would not and would target flanks and that these were ornamental or not. In short, the only real consensus is that there is no real consensus as yet.

This may come as a surprise as despite the obvious controversial nature of many questions in palaeontology many are at least close to a consensus or the evidence has started to tip decisively but here this is not really the case. Part of the problem is likely to be the sparsity of material – pachycephalosaurs are not known from many good specimens at all (half a dozen are known from only skulls, partial skulls, or just the domes) and some aspects of their anatomy are thus not well understood. Combined with the relative lack of interest in this clade (since almost everyone seems to prefer theropods) it is perhaps less of a surprise.

Pachy0532The lack of material in Europe especially and the fact that the group is not half as well known as the ‘classics’ like tyrannosaurs and ceratopsians, and their relative small size means that they rarely make it into dinosaur halls outside North America so I was pleased to see two different displays of them in Japan – the first time I’d actually seen any. At the top we have a butting pair from Tokyo and below the front/side and back of a skull from Fukui (both images used with permission). I hope more research goes into this area as it is genuinely fascinating and covers various aspects of mechanics, ecology and behaviour that integrate well and of course the application of data and studies from living animals would be especially useful.

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Baby killers: hunting and feeding behaviours of large theropods

adino256 For those who are regular readers this post clears up the mystery of the Thursday post –my new paper is out. It’s time for me to be a bit self indulgent on here as I have a new paper out that I imagine will be of interest to quite a few people on the web. My interests in palaeontology have always veered strongly towards behaviour and ecology and this is my first paper that deals with it in some depth, so please allow me to expound on this at length and forgive the excesses. Right, onto the actual content!

Continue reading ‘Baby killers: hunting and feeding behaviours of large theropods’

Ludodactylus

CIMG1091As (vaguely) promised, here are some photos of this wonderful ornithocheirid pterosaur. However the damned thing is so big (the slab it is on is close to a metre on each side as I recall) that it was hard to fit in the frame of the shot, even from on top of a chair so it doesn’t quite fit as you can see, hence the inclusion of a second ‘angled’ picture below to show it off better and a close-up of the jaws.

Continue reading ‘Ludodactylus’

Theropods are clappers, not slappers

One of the most pervasive but subtle errors of the Jurassic Park series LINK is the idea that theropod hands kind of fold forwards and down as if they are about to slap their thighs in some entertaining dinosaurian Bavarian dancing routine. In fact the palms of the hands should face inwards as if about to give a nice round of applause. Theropods were clappers, not slappers.

This is pretty pervasive in the minds of the pubic from the iconic moment of terror-inducement to children as a Velociraptor opens a door. It’s interesting to note that people seem to have accepted this position of the manus as more or less de-facto correct without even thinking about it. I have recently done a bit of work on a dinosaur book for kids and I think every single theropod that was sent to me had slappy hands. Every single one I sent back and told them to reorientate them, because they were wrong and that they didn’t look like that in pretty much any theropod and then a week later the next one would come in and well, you can guess where the hands were.

Milner et alWe actually have good evidence from two very different sources that theropods could not put their hands in this position (well a few derived ones may have been able to approach it). Most obviously when we have good 3-D skeletons we can simply articulate the bones to see A) what their natural position was, and B) how well they could pronate the arm (that is rotate the lower arm at the elbow towards a slapping position, something humans are exceptionally good at). Secondly we can see that even when actually wanting to do something like support the weight of themselves which you might think you’d really want to use the flat of your hand, rather than just the edge a theropod still does not (or more likely therefore cannot) pronate the hand. This comes from a recently reported fossilised print of a resting theropod with nice prints for the edges of the hand.

I should add that as ever this is biology and well probably they could we really can’t be sure exactly how they folded their arms. Doubtless some were better at this than others and could be proper slappers if you like and of course even those which you might call a ‘true’ clapper, could still pronate a bit, but as a general rule of thumb this is portrayal is accurate.

So the next time you see a slap-handed theropod remember to clap. Hmmm, that sounds awfully like the last ‘advice to kids’ line from the end of an 80’s cartoon. I think I’d probably better stop about there.

PS Thanks to Jerry Harris, Andrew Milner and Corwin  Sullivan for discussions on this one, a bit out of my normal range.

A bit on the ‘fighting dinosaurs’

IMGP0681There are many dinosaur (and other fossil) specimens that are famous not so much for what they are as what they show (as with Big Mama featured here the other day). A complete T.rex is all very well (and very useful and interesting and fundamentally cool, I’m happy to admit), but some things are so incredibly rare and unlikely to preserve that to have them as fossils is truly amazing. The most obvious archosaurian example of this is the famous fighting dinosaurs of Mongolia that show a Velociraptor and Protoceratops locked in combat. These have become the subject of much analysis and much speculation as to quite how they died and got preserved in such a posture.

IMGP0670

I’m going to join in that debate any further but merely point out that the Velociraptor has its foot claw jammed up in the throat region of the Protoceratops, but equally has its arm stuck in the mouth of its adversary. They may or may not have died together, but it is certainly possible that this was a case where each killed the other. It’s also worth noting that they are preserved pretty much in 3-D and have not collapsed into the sand as one might expect, something that is actually quite common in specimens from the area.

IMGP0692

These photos are of a fantastically well made cast of the pair that are on display in Japan. While photos of the original have been reproduced many times in all kinds of media, they always seem to be of the same shot, or at least one taken from the same angle, so hopefully these will provide some interest.

IMGP0703

While the photos are mine, I have graciously been given permission to post these by the Fukui Prefectual Museum. Please do not reproduce these.


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