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Pack-Hunting Dinosaurs Found As Large As T-Rex 156

1369IC writes "The Washington Post is reporting that the recently unearthed Mapusaurus roseae was as large as a T-Rex and may have hunted in packs. The fossils were found in Patagonia, in Argentina, though not enough were found to reconstruct an entire specimen. The meat-eaters probably lived in the same time and place as the 125-foot-long Argentinosaurus, the largest known dinosaur." From the article: "T. rex was equipped to attack and destroy animals its own size, Currie said, but Mapusaurs perhaps could 'go in, strike, pull and see what to do next,' a strategy that could work against larger animals, especially if the predators attacked together -- the prehistoric equivalent of a pack of wolves cornering a bison."
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Pack-Hunting Dinosaurs Found As Large As T-Rex

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  • Mapusaurs perhaps could 'go in, strike, pull and see what to do next,'
    'Hey, this piece came off, what do I do with it next?'
    We need a PhD in Dinosaur Psychology here.
  • "The problem, though, is that when you have only one incidence you really don't know what's going on."

    So the herd idea is just that, an idea.
    • Re:From TFA (Score:1, Insightful)

      by Anonymous Coward
      Yeah, it's an idea, but there is some evidence for it. It is based on the co-occurrence of 7 individuals of the same species. There are alternative explanations for such accumulations besides herding behaviour, but it is an interesting observation. There aren't that many discoveries of large carnivorous dinosaurs all in one spot like this.
      • I'm not sure which is more likely; that the seven animals were part of a pack, or that they all crashlanded in the same spaceship.
    • One struggles to call paleontologists scientists any more than you would call craneology a branch of medicine.

      Paleontology is full of crazy speculations that have very tentative grounds. When I was a kid, the biggest dinosaur known to man was the brontosaurus, which we later find was a mix of two or more sets of bones. Watch any Discovery Channel dinosaur documentary and you'll see that a fragment of a tooth gets extrapolated into an animal.

      • Watch any Discovery Channel dinosaur documentary and you'll see that a fragment of a tooth gets extrapolated into an animal.
        And watching Disocvery Channel dinosaur documentaries is definitely the best way to judge an entire field of professional researchers. So what percentage of the time do you suppose paleontologists are right with their classifications?
      • Your Discovery Channel?

        Your problem with paleontologists is that you don't understand how science works. In many scientific fields you have to especulate in order to do any useful work.
  • ...proposed that some larger macropredators would have needed to revert from predation to scavenging in adulthood is guilty of dumbassery of the highest order.

    A very simple counter-example exists. Watch a documentary about a large, muscle-bound, lumbering grizzly bear snatching a leaping fish out of thin air.

    Otherwise a neat find marred by an article economical on content.

    -Glee
    • [Whoever] proposed that some larger macropredators would have needed to revert from predation to scavenging in adulthood is guilty of dumbassery of the highest order. A very simple counter-example exists. Watch a documentary about a large, muscle-bound, lumbering grizzly bear snatching a leaping fish out of thin air.

      Obviously you know very little about predators. First and foremost, grizzlies are not "muscle-bound and lumbering", they are surprisingly quick and agile, and I'm willing to bet your life t

  • by Doug Dante ( 22218 ) on Tuesday April 18, 2006 @09:58AM (#15149166)
    " Some researchers have proposed that the juveniles may have been the pursuit predators of a pack of hunting T rex.". random link [fossilmuseum.net].

    This is commonly mentioned on the Science Channel [discovery.com].

    • " Some researchers have proposed that the juveniles may have been the pursuit predators of a pack of hunting T rex."

      ... to swallow the T rex which swallowed the cat which swallowed the mouse...

  • So now we are learning that dinosaurs are capable of effectively dealing with things in a group. Does this put dinosaurs at the same level as cockroaches? Perhaps, conversely, this means that cockroaches are as dangerous as dinosaurs?

    Perhaps, given sufficient numbers, prehistoric cockroaches could take out much larger animals, too...like the T-Rex.

    Aah...that would be a sight to see.

  • Did anyone else read that and think 'SCO'?
  • I can see it now... dozens of dinos screaming at a pack member to learn to pull :)
    • Dino Monk: I'll go into the herd and gain aggression from the brontos.

      Dino Warrior: Ok, when you get to about halfway back here, fall down and play dead.

      Dino Wizard: They'll think you died of a heart attack or something!

      Dino Warrior: Right. Then, when the majority of the brontos chasing you turn around and head back to the herd, I'll run to you and wave my ass at the one in the back. He'll be so pissed he won't call for backup and he'll come alone.

      Dino Monk: Right! feign death 4tw~!
  • TFA: loada crap (Score:2, Interesting)

    by BadDoggie ( 145310 )
    T. rex was equipped to attack and destroy animals its own size,

    Yeah, and every woman is equipped to be a hooker. The facts on T-Rex show the animal very unlikely to have been a predator. The general concensus of the predation deissenters is that the T-Rex eyes were small and likely couldn't have seen and tracked prey; the arms were too small to hold prey, and its oversized legs would slow the beast too much to be a decent predator. This last point may not be as important considering some of the larger spe

    • Many elephants go to "elephant graveyards" to die; will scientists in 60 million years stumble across one of these graveyards, see the tusks and the size of the animals and conclude the elephant was a vicious carnivore which hunted in packs?

      If the scientists of the future still have any brains left, they will look at all the teeth and be able to say that the Elephant was a herbivore... Those tusks were probably for defense.
      Granted, you may be right about the fossils found together: it may have been a d

    • Yes, T-Rex was most probably a scavenger. Google for it, and you'll see.
    • parent: loada crap (Score:3, Informative)

      by flyingsquid ( 813711 )
      (1) eyes are relatively smaller in larger animals. Adult humans have smaller eyes than infants, for example. T. rex and other large, carnivorous dinosaurs have relatively small eyes, but that's exactly as you'd expect. (2) plenty of animals manage to take down prey just fine without the use of arms. Sharks and crocodiles, for instance. (3) Concerning healed wounds, plenty of broken and healed bones are found. The problem: how do you tell it was T. rex that did it? Some healed breaks have been identified a
    • Re:TFA: loada crap (Score:5, Insightful)

      by Conanymous Award ( 597667 ) on Tuesday April 18, 2006 @10:54AM (#15149806)
      Was the T. rex a vicious predator or a lumbering scavenger? You seem quite confident with your position, but at the same time you forget about the facts that point to the other direction.

      Arms? I don't need no steenking arms to be a predator! If small arms == scavenger, most of the big theropod dinosaurs would have been scavengers. Not likely. Sight? The brain of T. rex seems to indicate it had an excellent sense of sight. Smell and sense of balance, too. Feet? Yeah, T. rex probably wasn't a sprinter. But it was very heavily built, which could mean a position as a top predator that took on the biggest, slowest and heaviest herbivores. As you already mentioned yourself, it may not have needed to be quick. It's neck is as strong as anything found in dinosaurs, but apparently at the same time it was able to make very fast and coordinated movements. Predators can also get big to be able to hunt big prey, and dinosaur prey-predator ecology was very likely to be different from its mammalian equivalent. Yes, T. rex was around right up until the KT extinction, but it wasn't there since the dawn of dinosaurs. It was actually one of the last dinosaur species known to have evolved, along with the likes of Triceratops and other late Cretaceous dinosaurs.

      So, make of these facts what you will. The only true fact, though, is that T. rex could have been an active predator or a scavenger. We simply don't and cannot know for sure. My take is it was probably both. A carnivore that big should have eaten tonnes of dead meat regularly to stay alive, and I find it unlikely that dead dinosaurs big enough to satisfy a T. rex's hunger were lying around in that large numbers. Just like lions today, it would be happy with a carcass in case such was easily available. As for pack hunting, that's mostly pure speculation.

      Oh, and the carnivorous fossil elephants of tomorrow. As it was already pointed out in another reply, the future paleontologists would look at the molars of the elephants and make the right conclusion that the animal was a herbivore. Size doesn't make animals carnivores, neither elephants nor dinosaurs.
      • ...look at the molars of the elephants and make the right conclusion...

        Personally, I think they will look at the size of their trunks and
        conclude they were pack rats.

        (that is a joke - get it?)
      • The brain of T. rex seems to indicate it had an excellent sense of sight. Smell and sense of balance, too.

        No soft tissues of T. rex have ever been found. All we know is the average size of the brain of T.rex, and very little about the prominent parts of that brain and its function. So I think it is too much of a stretch to say that the brain of T.rex indicates that it had an excellent sense of sight, smell etc.
      • About the pack behaviour of animals - it is very difficult to ascertain whether a animal is a solitary hunter or a pack hunter by just looking at fossil remains.

        Case in point - consider the panther and the lion. Panthers are shy solitary hunters, while lions typically live in a pride and do hunt in packs. However, the fossil remains won't indicate anything about this.

        • You are very unlikely to find fossils of 20 or 30 panthers in one place simply because they don't gather in such quantities.

          You are more likely to find remains of lions in groups if a catastrophy (volcano eruption, sudden flood) catches them all up.

          From this you can make some informed guesses.
          • Carcasses of animals can quite often be found lying in groups in a small area following events such as flooding when animals retreat to whatever high-ground they can find. Also, if carcasses are floated down a river, they can get stuck around rocks or obstacles. So there can be multiple explanations for why bones of animals can be found together.
    • Here's the kicker. Most predators are scavengers. It requires less energy to scavenge than to hunt and kill. T Rex was very capable of killing. Nature wouldn't have made those tools (powerful legs and huge sharp teeth) if it didn't intend for him to use them.
      • Nature wouldn't have made those tools (powerful legs and huge sharp teeth) if it didn't intend for him to use them.

        Right. Like the rapacious pack-hunting elephant and kangaroo.
    • I don't think there's a consensus on this issue; only one palentologist, Jack Horner, seems to be making this claim. While some of his assertions make sense (the ability to sniff a carcass, limits on upper speed, etc..) T-Rex had binocular vision which is normally the mark of a predator.

      In addition, the two feeding styles aren't exclusive: modern predators are certainly willing to still other's kills and just generally scavenge when they have to - and while your remark about no healed wounds seems to be wid
      • Re:Down boy! (Score:3, Interesting)

        by jc42 ( 318812 )
        [W]hy would T-Rex need such a formidable jaw if it was only scavenging and not killing?

        Others have mentioned modern lions, and that could be a partial answer to this question.

        Field researchers studying lions have reported that, in many areas, they rarely find instances of lions killing their own prey. Rather, lions mostly steal the prey of smaller predators like hyenas and wild dogs. If you're as big as a lion, that can be an easier way of making a living than hunting and bringing down your own prey. This
        • Although I have to imagine that with the smaller cranial capacity, T.Rex's hunting strategies were probably much simpler than those of modern cats.

          Actually, on reflection, that actually supports your point - it's easy to imagine T.Rex having a simple pattern of "smell meat, locate meat, chase away anything between you and the meat, eat."
    • How would a scavenger get to be larger than most predators?

      I dunno, the T-rex looks ALL predator to me, It could Grab with its teeth while giving blows with its legs and sharp claws.
      • I think it's more of *WHY* does a scavenger get to be larger than most predators. Easy, if you're bigger and more menacing, it makes that much easier to take a kill from something else.
    • The fact that large herbivorous dinosaurs, such as Triceratops, developed significant defensive capabilities suggests that large predators existed and were important.
      • Or, it could suggest that these defensive capabilities (huge horns, plates, etc) were overkill and more related to mating. They may have started as defensive capabilities, but could have very easily grown into something that's more ornamental. I'm not saying that IS the case, just that it's possible.
    • Re:TFA: loada crap (Score:3, Informative)

      by Miraba ( 846588 )
      "Given that, I'm loathe to accept some conjecture about some other animal that supposedly lived and hunted in packs based on the spurious evidence of a group of bones comprising many species members and none of which comprise more than 80% of a single animal."

      Actually, 80% recovery of an organism is nothing to sneeze at. (And where did you pull that number from? I haven't seen it anywhere and I just scanned through the paper.) Consider how many species are known only through teeth, skull fragments, and t

    • It's important to remember that this is the consensus of "predation dissenters" like Prof. Jack Horner... those who don't think that T-Rex was a predator. So, that list is a little biased. And, as my paleontology professor told me, "Jack doesn't like T-Rex because it eats his duckbills..."

      Yes, T-Rex's vision may not have been great, and the forelimbs are human-sized (as in, you'd have a 50/50 chance of beating T-Rex in arm wrestling...). None of this really argues against predation though.

      T-Rex may not h
    • Many elephants go to "elephant graveyards" to die; will scientists in 60 million years stumble across one of these graveyards, see the tusks and the size of the animals and conclude the elephant was a vicious carnivore which hunted in packs? And will that era's Slashdot splash such spurious findings on the front page?

      Others have addressed the nonsense about tusks/teeth, but I should point out that the distribution of different sized specimens (read: different ages) is strongly indicative of a living pack

    • Just a hint: when sorting comments after rating, this ignorant idiot of parent still gets the first place with his +5 insightful blabering.

      Maybe that should change?
  • "the recently unearthed Mapusaurus roseae was as large as a T-Rex and may have hunted in packs
    [...]
    the prehistoric equivalent of a pack of wolves cornering a bison
    "

    Yikes - where's this fossilized bison that's 10x as big as a T. Rex?
    • > > the recently unearthed Mapusaurus roseae was as large as a T-Rex and may have hunted in packs> >
      > > [...]
      > > the prehistoric equivalent of a pack of wolves cornering a bison"
      >
      > Yikes - where's this fossilized bison that's 10x as big as a T. Rex?

      Never mind that. T-Rex hunted in packs? Where's the pack big enough to hold a T-Rex and one of these megabiso- oh, never mind, I see the pack.

      (It's the one Chuck Norris is wearing.)

    • Sarcasm is good - Provided one knows what he is talking about.
      The answer is there in the article (actually in the summary itself).

      On an average - Tyrannosaurus rex was roughly 5 to 7 tons in weight.

      FTA
      Researchers said that by working together the dinosaurs may have been able to kill animals much bigger than themselves, including the 125-foot, 100-ton Argentinosaur
      • RTFP: Knowing what you're talking about is good - provided there was sarcasm in my original post.

        BTW, I made a joke only of the wolf [wikipedia.org]:bison [nhptv.org] ratio, 137.5:1175 pounds, or 8.5 - roughly 10x. If Mapusauruses cornered their prey like wolves cornering bison, that prey would be 10x the size of the Mapusaurus, said to be the size of a T. Rex, therefore 10x the size of a T. Rex.

        Keep you ininformed, uninsightful, obnoxious sarcasm to yourself.
    • "Yikes - where's this fossilized bison that's 10x as big as a T. Rex?"

      In Sauropoda. It's interesting to see that in early to middle Creataceous South America there are plenty of huge sauropods, while elsewhere in the world they were on a decline at those times. And along with the huge sauropods there were loads of huge predators, more than elsewhere. The late Cretaceous North-American Tyrannosaurus looks like quite an anomaly, a huge predator where it seems it didn't need to be, but there's nothing out o
  • Googlemapusaurus!!~~~!!

    - Andrew
  • "The Washington Post is reporting that the recently unearthed Mapusaurus roseae was as large as a T-Rex and may have hunted in packs."

    Am I the only one who saw a trailer for Jurassic Park 4 beginning to flash before my eyes as I read this ?-)

    Hey, let's make even better ! Let's make Star Wars Episode 7, complete with a final battle with a whole fleet of Death Stars (Death Cluster ?-) !

  • These guys sound like a perfect "3rd faction to join the fight" plot twist for the surely on its way live action Transformers 2: Dinobot Island!
  • Lions vs Tigers (Score:2, Insightful)

    by Gorimek ( 61128 )
    Here's a fact: Lions hunt in packs. Tigers hunt alone.

    I'd love to be proven wrong, but I doubt there is any way you can tell that from looking at their skeletons, or even a dead body.

    Animal fossils can tell us a lot about past species. But there is also a lot they can't possibly tell us.
    • There was a grouping of the fossils ... like they all died together. Hence they lived together. Lions living together, hunt together so they can take down a bigger animal.

      If (when) something major causes a mass die-off of lions and tigers a pride of lion's bones would later be discoverd together, while tiger bones will be found alone.

    • Re:Lions vs Tigers (Score:2, Interesting)

      by MrFebtober ( 922100 )
      One of the clues on fossil skeletons to look for that paleontologists use is healed injuries. If, for instance, you find a smilodon fossil showing that an individual suffered a crippling leg break that had partially healed up (but never fully recovered), you have a strong indication that this animal was probably kept alive by getting food from others as it was most likely incapable of hunting for itself or adequately defending itself. Therefore, it seems more likely that this was not a solo hunter and likel
      • a smilodon fossil showing that an individual suffered a crippling leg break that had partially healed up (but never fully recovered), you have a strong indication that this animal was probably kept alive by getting food from others as it was most likely incapable of hunting for itself or adequately defending itself.

        This argument is made particularly for the human species and its relations. Neanderthal skeletons showing extreme arthritis, healed broken bones that would have incapacitated the individual at

    • Re:Lions vs Tigers (Score:3, Interesting)

      by 1u3hr ( 530656 )
      Here's a fact: Lions hunt in packs. Tigers hunt alone. I'd love to be proven wrong, but I doubt there is any way you can tell that from looking at their skeletons, or even a dead body.

      Bones from several specimens were found together, apparently contemporaneous; and no other animals. The supposition is they were together and killed suddenly, perhaps a flood. They wouldn't be socialising unless they had a good reason -- if they were lone hunters or scavengers they would keep well apart and guard theie terr

  • Dinosaurs rock! (Score:3, Insightful)

    by ursabear ( 818651 ) on Tuesday April 18, 2006 @11:19AM (#15150091) Homepage Journal
    Honestly, dinosaurs are great stuff for the imagination and for science. I think funding for physical sciences benefits from stories about MassiveTeethOSaurus. I agree that many conjectures, assumptions, and claims (in articles like these) tend to be very imaginative compared to the hard facts known.

    With all that said, dinosaurs have always been really interesting to me. (Often) big, different, not around any more, lack of details (the mystery), (did I mention many of the cool ones were BIG? Well, maybe compys are pretty cool, too...) - all good ingredients for imaginative fuel. I digress. Sorry...

    I always take news releases and articles like these with a grain of salt. Much of the publicized (read: made more interesting and made less dry) aspects of dig findings are generally lots of intelligent conjecture. That's OK with me, provided that folks don't assign the gloss (of the articles) to be factual. Did they hunt in packs? Did they hunt or scavenge? Were they gray or were they colorful? Some things we may never know... but for now, discoveries like these are just like candy - lots of fun.
  • "The meat-eaters probably lived in the same time and place as the 125-foot-long Argentinosaurus"

    And people accuse us yanquis of hubris?

    Did it inhabit the Malvinas?
  • Seems like these very large dino-predators were more likely to use the hunting technique of the Komodo Dragon: simply run up and take a bite of your prey, and then follow it for 3 days while it dies of blood poisoning.

    The Komodo's teeth are positively filled (in fact there's special grooves to retain the bacteria!) with pathogenic bacteria.

    I wonder if these new dino's have similar grooves in their teeth?

    We know from the math, that a predator of this size can't take too many falls, as their own weight is mor

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