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Puberty Blues for the T.Rex 59

An anonymous reader writes "A new press release about Tyrannosaurus Rex shows that they lived fast and died young. Growing at 2kg per day for up to 10 years. Links to summaries on BBC and CNN."
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Puberty Blues for the T.Rex

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  • by Anonymous Coward
    ...they had to enter carousel.
  • by cjpez ( 148000 ) on Thursday August 12, 2004 @11:39AM (#9948464) Homepage Journal
    I mean, they are the "experts," and I'm just some guy in front of a computer, but what kind of caloric intake would it require to grow 4.6lbs in a day? Was the T.rex a carnivore? If so, you'd think it'd be pretty difficult to kill enough STUFF to be able to do that.

    I've been looking around trying to find data on growth rates of other larger animals (elephants were mentioned on the CNN article, and I figured whales may be useful), but all I seem to be bringing up is growth rates in terms of population, not physical weight.

    • According to the most recent studies - and those are just some scientist's claims, mind you - the T Rex was a scavenger - in other words, it rarely if ever killed its own prey. Which in my opinion implies that it was an omnivore rather than a carnivore.
    • by Ayaress ( 662020 ) on Thursday August 12, 2004 @11:47AM (#9948593) Journal
      There have been a lot of people who believe that T.rex was a scavenger for a variety of reasons. They're clearly able to kill by sheer size, but I find it reasonable that that wasn't their main survival strategy.

      A sparsely populated scavenger, particularly one that could still kill smaller prey (of course, by "small" in this case I'm still talking about things the size of a Buick) would have a much easier job eating that much.

      Also, remember that the animal's their eating (wether scavenged or hunted) were as large, and in some cases much larger, than they were. A dead sauropod could likely feed several T.rex for some time after the kill, in the same way that a wolf pack can spend several days eating a large moose.
      • As another poster mentioned T-rex was big. Lions are excellent scavengers because they are big. Most predators scavenge if they get the change but it helps if your big enough to scare others away. Being able to claim any food source by your size, wether that food is still runningm, you just killed it, killed by someone else or dropped dead of old age, is a bit of an advantage.

        It also works for herbivores. Elephants can be big and smart because they are big and smart. Big enough to stand up to a lion and sm

        • There are several reasons for an animal to die young:
          1. It has internal weaknesses which prevent it from living long.
          2. It lives in an environment which is likely to kill it regardless.

          T. Rex was big, each adult representing a huge investment in energy. It would make sense for the species to live long so that each adult could reproduce as much as possible, so the internal weaknesses would tend to be selected against. But what about 2? If the environment (including other T. Rex's) made it very unlikely for an

          • Other dinosaurs also didn't live long. I've seen estimates that large sauropods didn't live over 30 to 50.

            There's another reason they didn't evolve intelligence enough to escape their own destruction, as well. They fell into a lifestyle that didn't require it. Humans became intelligent partially because we didn't really have much else going for us. We weren't fast enough to catch prey, we didn't have furr to stay warm at night or dry in the rain, we didn't have the size to discourage predators or the stren
            • we didn't really have much else going for us. We weren't fast enough to catch prey

              There's a theory out there that we really were fast enough to catch almost anything...
              I've seen it in a few forms, proposed by human biologists [], anthropologists [], and even hard science fiction writers [].
              What's significant, however, is that it frames our ancestors as endurance runners, and suggests that we tended to run down prey by shedding heat better (keep in mind where we evolved) and absorbing and disipating shocks in our

            • I believe that we evolved both culturally and genetically to be able to get clothings (leather at first) and THEN we evolved genetically to not to have fur.

              That's logical to me. What other reason could you imagine to not to have fur?

              And that furless also created the concept of being naked, but that's other topic.
      • Aaah, yes. I hadn't considered scavenging. That makes a bit more sense then. Thanks!
    • Fast growth in living organisms isn't that unusual. There's bacteria (with the old example of a single bacteria cell multiplying quickly enough to cover the Earth in a day - under ideal conditions, of course). But even multicellular organisms grow fast, too. Some species of bamboo can grow six inches per day. Giant pumpkins can get 10 pounds heavier each day. In some parts of Alaska, the crops have much less time to grow than in the rest of the country, and yet the produce is HUGE (I'm talking heads of
    • Well let's see. Elephants are born around 200 lbs and reach full size by age 20. Full size females are around 6-7000 lbs and males around 11-13000 lbs. So let's say 10,000 lbs (to facilitate simpler math) over 20 years (assuming steady growth, though it probably isn't) would be 500 lbs per year or 1.4 lb per day? I'd assume more of the growth would occur in the first few years since just about everything grows that way, so it may be more like 3-4 lbs per day in their youth. But I'm just speculating. D
      • Herbivores have an easier time growing fast, though, since they can eat just about everything around them, and generally don't have to fight their food to the death. Which brings me back to my scavenger point: This is another big of evidence that T.rex was at least partially a scavenger, especially with the sheer size of animals like sauropods. With herds of sauropods around, you'd expect a couple fifty-ton corpses laying around at any given time. That's more than enough to fuel that sort of growth in a la
  • T.Rex (Score:3, Funny)

    by darth_MALL ( 657218 ) on Thursday August 12, 2004 @11:47AM (#9948596)
    used to rock the house. Until the pedophile charges, that is. Oh wait...that was Gary Glitter. My Bad.
  • RTFA. The 2kg/day growth lasts for 4 years during adolescent. The life span seems to be 20-28 years.
  • by cephyn ( 461066 ) on Thursday August 12, 2004 @12:03PM (#9948804) Homepage
    To sustain that kind of growth rate, i think that pretty much proves t. rex was a predator first and a scavenger second, and a pretty fearsome predator at that.
    • I'm curious how you'd come to that conclusion?

      For overall growth you also have to consider activity... wouldn't t'rex burn a LOT more calories hunting than scavenging?? I'd think the info leans more toward supporting the idea of t'rex in all his fearsomeness, chasing away the hunters to move in on their kill.

      Coming soon to a theater near you: Predator v. Scavenger! umm...

      • by cephyn ( 461066 ) on Thursday August 12, 2004 @12:16PM (#9948964) Homepage
        yeah it burns more calories, but the rewards are MUCH higher. otherwise you have to wait for something to die, or be in the right place at the right time to chase someone else off.

        I bet t. rex followed a pattern like lions....mostly lazy, but hunt when hungry....and if they happen on something dead, fantastic! bonus!
        • Lions are quite adept scavengers. They make relatively few large kills themselves (especailly lone males), but pretty much have their pick of kills from other large cats, hyenas, and wild dogs. Hyenas, on the other hand, despite common belief, are the truely fearsome hunters of the region. They have one of the higest success rates in hunting of any carnivore. So do the African wild dogs for that matter. Neither one, however, is very good at keeping their kills when a pride of lions happens by. Cheetahs have
          • im not saying they were EXACTLY like lions. just similar in that i bet when they weren't hunting, they were very sedentary. probably gorged on huge meals so that they wouldnt have to hunt every moment. Remember, their prey was giant sauropods...HUGE meals. could eat for a couple days on it as long as they sat by the kill.
          • Leopards particularly will steal their kills at every turn.

            Yeah, I saw that once on National Geographic once:

            Wildebeest takes 65 points of slashing damage!
            Wildebeest is slain by -=l3pp4rd=-
            CH3374-X: j0 d00d! WTF! u stole my kill!111
            -=13pp4rd=-: HE AGGROD ME
            CH3374-X: STFU b1tch. now I hav to regen stam.
    • being a predator takes a LOT of energy(running around).

      if you're the meanest creature in the block you can however just claim anything that someone else is eating(or if that someone else refuses just eat it too). depending on the habitat that may very well be a ticket to eating more with less energy spent on looking for the food(which is the whole point, having to spend less energy to find food why one would assume t-rex to have been a scavanger).

    • How in the hell did you come up with that "proof?"

      Hunting uses a shitload of calories. Look at a cheetah vs a lion. A cheetah hunts and is skinny, while a lion is both a predator and scavenger and is much larger. An even better example is a female lion vs a male lion. The females hunt and are skinnier, while the males generally scavenge and are larger.

      This growth rate isn't all that spectacular. Elephants and whales both acheive similar rates and they don't really hunt (baleen whales eat live prey, b
  • Giganotosaurus (Score:3, Interesting)

    by pipingguy ( 566974 ) on Thursday August 12, 2004 @12:27PM (#9949126)

    What about Giganotosaurus []?
    • From your link,
      Giganotosaurus and T. rex lived in different places and at different times
      I doubt there were many cases of T. Rex having to fight this guy over a kill...
  • by TheLink ( 130905 ) on Thursday August 12, 2004 @12:31PM (#9949189) Journal
    Sure the T Rex probably doesn't run that fast. But how fast can one of those huge sauropods run anyway?

    Not saying that T Rexs don't scavenge. But why do so many people claim it's a scavenger just coz it can't move that fast? It only needs to move faster on _average_ than the prey. Even if the prey is faster at first, if the prey gets tired first and stops running, it's munch time.

    Heck it only needs to bite off a 50kg bit of a sauropod tail every day or so and you should do the 2kg weight gain/day pretty easy, and the sauropod will probably just grow it back - 50kg out of 50 tons is like a 70kg human losing 70g of flesh+blood.

    A sauropod could probably seriously injure a smaller predator dinosaur, but it should be harder to keep away a T Rex.

    • I'm trying to find a link that isn't on a children's site. The major reason was speed. They couldn't move as fast as most bipedal herbivourous dinosaurds could. Some claims have been made that sauropods are about the same speed, and other that T.rex was faster.

      Those tails coud easily break the sound barrier by turning their bodies. A monitor lizard can break a man's legs or back with their tail just by twisting their body slightly, and they're generally smaller than humans. Sauropods are much larger than T
      • Y'know it may take a few seconds after the tail is chomped before the sauropod's rear brain actually realizes the tail is bitten and begins preparing it for supersonic speeds :). May be time enough to get clean away.

        If there are plenty of obstacles around (trees, big plants, rocks) then tail swinging isn't going to work well.

        Would the smaller/younger sauropods be faster than a T Rex? What's worse if they are moving through uncleared terrain. The T Rex behind just has to follow the "trail" the prey makes/c
  • IANAP (I am not a paleontologist), but...

    Remember, folks: most scientists are of the belief that dinosaurs, including T.Rex, were cold-blooded. That means that the calories that mammals usually
    use to maintain body heat (a VERY non-trivial amount) are not spent by reptiles. Thus, more of their caloric intake was diverted to their growth rate/spurts.

    Seems to me that should be factored into the equation when deciding how much food an animal must consume to put on the pounds?

    Thoughts? Am I off-base
    • Possibly. There has been discussion in recent years that they were warm-blooded in some ways. More info here [].
    • Am I off-base here?

      Well, sorta yes and sorta no. There's argument both ways on the warm blooded/cold blooded issue. There's no general consensus either way. The evidence goes in different directions, and I don't really see anything here that would break the camel's back. (granted IANAP either)

      Cold blooded animals do have a larger portion of their energy intake available for growth, but they also typically eat less, owing ot their inability to maintain the levels of activity a warm blooded predator can, g
      • It's not so much to do with metabolism.

        A species "natural" lifespan appears to be more linked to how likely a creature is to die of reasons other than old age.

        It is unlikely you'd evolve a body that'll last 200 years when you're likely to be eaten by the time you're 5 years old, or have a fatal accident.

        That's the current theory why rats don't live for very long whereas bats do (up to 30 years for some bats).

        Compare the lifespan of tortoises vs snakes. And compare the types of snakes too.

        The creatures

Logic is the chastity belt of the mind!