Crouching dragon

One truly unusual and entertaining exhibit at the Tokyo Dino Expo 2011 was the mount of a Tyrannosaurs in a sitting position. And here it is:

Not only did this look great, and was something nice and novel, but for me it was nice to be able to access some bones rather more effectively than normal. My access to tyrannosaurs is generally limited to mounted casts, and while there’s the inevitable problems of things like the metatarsals overlying each other, and the ribs obscuring the dorsals, it’s made much worse when the skull and most of the vertebrae are several feet above you. Bringing the whole animal down to ground level made it much more accessible, and also helped demonstrate how certain things change with changing postures – just look at the flexion of the knee joint for example.

20 Responses to “Crouching dragon”


  1. 1 Zhen 17/08/2011 at 7:18 pm

    Personally, I think the 2 mating Tyrannosaurs are still the most unusual mount, but this is a close second. I can show this to others without blinding them.

  2. 2 Tomozaurus 18/08/2011 at 1:07 am

    In really want to draw this now. I think I shall, in fact.

  3. 3 Mark Robinson 18/08/2011 at 7:08 am

    Wow, that’s a great skeleton – the first decent photos I’ve seen of a mounted specimen of Tyrannosaurus with an apparent full set of gastralia. “Sue” was pretty complete but the Field Museum’s mount doesn’t show any gastralia at all.

    A layperson’s question: the semicircular bones to which the humeri and scapulae attach – are they the coracoids? I’ve always wondered what they looked like. I also hadn’t realised that they formed a sort of single surface at the front, a bit like a shield. Some mounts don’t appear to show this – is there disagreement on how these were oriented in life?

    • 4 David Hone 18/08/2011 at 9:02 am

      Yes those are coracoids and yes you will see them mounted in different ways. Or at least, how close the arms come together and if the coracoids meet can vary (their position relative to the scapulae and humeri is fixed). My understanding is that this is pretty much bang on though, and the presence of the furcula suggests.

  4. 5 Zhen 18/08/2011 at 4:15 pm

    Dave, does this expo happen every year in Tokyo? I’m vaguely aware of it, but after seeing your photos, I’m very interested to learn more. I’m hoping to plan a trip their one of these days if it’s an annual thing.

    • 6 David Hone 18/08/2011 at 5:11 pm

      There is an annual expo, but it covers all science, so vary year to year. Still, about 1 in every three years is dinosaurs simply becuase they are so popular.There will be another soon….

  5. 7 Sheila Chambers 19/08/2011 at 5:15 am

    I always thought that big “boot” on the pubis was crying out to be used as a prop when the tyrannosaur squatted down to rest or prior to lunging up to take a bite out of a passing hadrosaur.

    A tough, thick pad would have covered the “boot” and if tyrannosaurs had a bite like the Kommodo dragon with it’s nasty poisonous fauna, it’s keen nose would have followed the prey until it fell, no speedy running would be needed and it would not need to be just a plodding scavenger.

    One nasty, fetid bite would doom it’s prey.

    • 8 David Hone 19/08/2011 at 7:56 am

      Well it’s jsut too thin for any real support I think. The shaft of the pubis isn’t very broad and it’s not going to hold much weight, certainly not a few tons that are rockinging of shifting at the animal gets up, it’d just snap.

    • 9 Dave Godfreey 19/08/2011 at 5:51 pm

      While I’m sure <i.Tyrannosaurus probably did have some unpleasant mouth lfora, Komodo dragons are actually venomous. and its that that they use to unt their prey.There’s no good evidence of venom in any archosaur.

      There was a paper suggesting that there was a venomous troodontid a year or so ago, but which got pretty roundly criticised when it came out.

  6. 10 Sheila Chambers 19/08/2011 at 11:55 pm

    I don’t have access to a natural history museum so I can’t see just how robust T-rexes pubis might be. I think most of the weight would have been through the hind legs with just some of his mass on the pubis.

    As for his bacteria laden bite, I thought that that was one of the reasons the Kommodo dragon was such an effective hunter. Infect the prey with your nasty bacteria and poison then wait for it to die from septicemia & blood loss.

    T-rex wouldn’t have had poison but probably a very dirty mouth and it had large olfactory lobes so would have had a good sense of smell. He could track the sick prey down by it’s rotten stench just like the Kommodo dragon does.
    T-rex didn’t need to be fast, just have a dirty bite and let the bacteria do the rest.

    With such huge teeth and a powerful bite, the damage alone would leave a very messy, dirty wound and the warm mesozoic would be swarming with nasty “bugs”.
    Dinner is served!

  7. 12 Sean Webb 27/08/2011 at 10:22 pm

    @Sheila: There wouldn’t have been much of a need for T. rex to have the nasty mouth fauna you’re suggesting. Consider the following:

    “We kept the muscle numbers down because we thought they couldn’t possibly be that powerful,” Snively said. He noted that colleagues at the Tyrrell museum have shown that a T. rex’s lower jaw could apply 200,000 [44 961.788 774 lbs] newtons of force, or enough strength to lift a tractor-trailer.” – http://goo.gl/Dux7j

    There are certainly healed instances of bone on potential prey critters, but if a rex where able to get its mouth on its target, I’d say chances were not favorable for the prey walking away from the encounter with its life.

  8. 13 Sheila Chambers 31/08/2011 at 11:35 pm

    So if it’s prey had an immune system like a crocs, then it would be resistant to infection, but with such big strong teeth and bite wouldn’t a deep bite to the thigh damaging the bone & lead to infection or at least slow the beast down so it lags behind the others in it’s group for T-rex to follow and finish off?

    If T-rex wasn’t fast or nimble, it would make a good ambush predator,lunging up to give a deep, nasty bite in the flank or leg then follow using it’s fine sense of smell.

    For most animals, if it doesn’t move, it’s not seen so if T-rex didn’t move, it wouldn’t be seen until it was too late.

    I can’t see T-rex as a scavenger, it would starve. It could steal the meals of faster predators however.

    • 14 David Hone 01/09/2011 at 7:53 am

      “big strong teeth and bite wouldn’t a deep bite to the thigh damaging the bone & lead to infection or at least slow the beast down ”

      A bone-deep bite from a rex would kill just about anything in minutes becuse it would be simply bleed out. Dragons only slash becuase they are considerably smaller than the things they occasionally prey on, that’s simply not the case for Tyrannosaurus. If it’s a predator, it’ll simply bite to kill. And this all becomes largely irrelevant unless they are consistently going after giant herbivores which is unlikley.

      “For most animals, if it doesn’t move, it’s not seen so if T-rex didn’t move, it wouldn’t be seen until it was too late.”

      Sorry, just not true, and certainly not for birds and crocs and by extension, dinosaurs.

  9. 15 Sheila Chambers 05/09/2011 at 6:39 am

    Sorry but I must disagree.
    I have watched many videos of predators hunting. They note how often their intended prey raises it’s head to look around, then time their moves for when it’s grazing and freeze when it starts to raise it’s head. As long as the predator isn’t moving when the prey looks about, it’s not seen.

    The predator can get quite close before their intended prey finally sees it.

    Haven’t you ever misplaced something and looked for it but didn’t see it even though it was in plain sight?
    It didn’t move so we looked but didn’t SEE it.

    I remember another frozen prey animal, a robin crouched down on a branch it’s beak in line with it’s body, it didn’t move at all. in a nearby tree was a Sharp-shinned hawk which did not SEE the motionless Robin.

    To photograph birds or deer, I have to be sure not to stare at it and not to move when it looks in my direction

    Our eyes are very sensitive to motion especially at the periphery of our vision. It’s that sensitivity that makes people see something move out of the “corner of their eyes” when in truth, there is nothing their at all.

    I imagine that large Therapods were cryptically colored and at least some were ambush hunters.Just squat their partly hidden bulk down by some plants and wait motionless, for a meal to walk by. If you don’t move you won’t usually be SEEN.
    T-rexes small eyes would be difficult to see especially if it squinted.

    Human hunters also know that animals won’t see them as long as their not seen moving and the wind is favorable so their not smelled.

  10. 16 David Hone 05/09/2011 at 8:45 am

    “I have watched many videos of predators hunting. They note how often their intended prey raises it’s head to look around, then time their moves for when it’s grazing and freeze when it starts to raise it’s head. As long as the predator isn’t moving when the prey looks about, it’s not seen.”

    Yes,but those predators have things to hide behind. And squatting down when you are that sixe is not easy and would take you a long time to get up again. The biggest terrestrial obligate predators right now are lions, tigers etc. and they can simply hide behind grass, not so a 10+ m long Tyrannosaurus. What could it possibly hide behind? Even in dense forest it would be hard to conceal and that only makes it’s movements more limited. And what about predators that don’t hide and ambush things like wolves, hyena and hunting dog? There’s more than one way to hunt.

    “T-rexes small eyes ” Actually they have the largest orbit of any known terrestrail orghanism, they are the very anthesis of small.

    “Human hunters also know that animals won’t see them as long as their not seen moving and the wind is favorable so their not smelled.”

    Or heard. So there is another 2 factors it smell, sight and sound. Just ‘hiding’ is not enough and that’s very hard for a giant predator.

  11. 17 Sheila Chambers 05/09/2011 at 10:35 pm

    T-rex has small eyes! it’s orbit is only 4″ across and it’s eyes are small relative to it’s size.
    T-rex does not have the largest eyes either, a giant squid has eyes that are 20″ across.
    I bet there were other dinosaurs that had larger eyes than T-rex but I can’t find their measurements.

    I also don’t think it would take a “long time” for T-rex to stand up, I don’t expect it to leap to it’s feet like a kangaroo but those huge thighs and muscle attachments does not lead me to think it took very long to get to it’s feet. A slow dino is a dead dino.

    If a predator just stays motionless, it’s not likely to be noticed.

    Surely you have LOOKED for something but did not SEE it even though it was in plain sight. I’ve seen cars drive into a motionless train that had parked across the road.
    Didn’t they SEE it?
    clearly not.
    And it was not a “mini” train either.

    Animal brains are tuned for MOTION, if it doesn’t move, it won’t be SEEN in most cases.
    I have used this myself when stalking animals, make sure your not seen in motion as you work your way closer to your subject and of course don’t stink, don’t make a noise and don’t stare at it, look at something else.

    Like most predators, T-rex would have chosen the most vulnerable prey to attack, the old, lame and the very young and of course it wouldn’t have passed up a meaty carcass.
    I would also expect even a large theropd to have cryptic coloration so as to blend in with it’s environment.Splotches of green, tan, brown and straw would work in most environments.
    The mix would vary, pale in open environments, dark in forests.

    Too bad most of these fascinating animals were wiped out 65 million years ago but then why did croc’s, birds, lizards, frogs, toads, snakes and mammals survive?

    It could not have been just about size, some dino’s were small, endothermic and feathered but they are also gone.
    Why???

    • 18 David Hone 06/09/2011 at 8:53 am

      “T-rex does not have the largest eyes either, a giant squid has eyes that are 20″ across.
      I bet there were other dinosaurs that had larger eyes than T-rex but I can’t find their measurements.”

      I said terrestrial animal and squid do no live on land. And there is a paper on this by Stevens where he measures all manner of eyes (and especially large dinosaurs) and noted that rexy had the biggest.

      “I also don’t think it would take a “long time” for T-rex to stand up, I don’t expect it to leap to it’s feet like a kangaroo but those huge thighs and muscle attachments does not lead me to think it took very long to get to it’s feet.”

      But again, functional studies have looked at how they stand, and it’s not that quick. It would lose a couple of seconds on this, which is more than enough for any alert prey to get a decent head start. It’s just not that quick off the mark which ambush predators have to be.

      “Animal brains are tuned for MOTION, if it doesn’t move, it won’t be SEEN in most cases.”

      Unless they are looking for a particularly important shape, like that of a predator. And this point is somewhat irrelevant if, as I pointed out earlier, T. rex can’t just sit and wait for things to turn up (a tactic incidentally used only by animlas with low metabolism, other have to stalk things to get close and seek out prey, even if they are ambush predators). And of course they could still hear or smell it. And it assumes it could be hidden well in the first place.

      “Like most predators, T-rex would have chosen the most vulnerable prey to attack, the old, lame and the very young and of course it wouldn’t have passed up a meaty carcass.”

      Which borders on the point I made at the very beginning. Why do you need all this extrapolation of behaviours and hunting methods when the simple fact is it was probably going after things that couldn’t run away well or made dumb mistakes. This is pretty much normal for all carnivores (and especially targeting juveniles).

  12. 19 Zhen 06/09/2011 at 1:39 am

    “T-rex does not have the largest eyes either, a giant squid has eyes that are 20″ across.
    I bet there were other dinosaurs that had larger eyes than T-rex but I can’t find their measurements.”

    Dave said terrestrial organism, meaning animals that live on land. Giant squids would not fit in that description.

  13. 20 Sheila Chambers 06/09/2011 at 2:15 am

    It seems that Dromiceiomimus a rather small dinosaur had eyes as large as T-rex, about 3″.
    A ostrich has eyes that are about 2” in diameter but very large for it’s size.

    I’ll have to stand corrected on T-rexes eyes, I don’t know of any other dinosaur that has larger eyes than T-rex.
    But some seem to have eyes as large as T-rex in a much smaller body.

    Why did only flying theropods survive the K-T extinction event?


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