Tyrannosaurus rex hunted for live prey

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Tooth found in victim's tail shows carnivorous dinosaur did not just feed on carcasses.


Audiences the world over gripped their seats as the Tyrannosaurus rex in Jurassic Park sank its teeth into velociraptors and chewed up avaricious lawyers. In spite of this portrayal, there was no hard evidence at the time that the dinosaur actually bit into anything living, and some palaeontologists have proposed that it scavenged for its meals. But now, a team has found definitive evidence that the T. rex did hunt for live prey.

The researchers found a T. rex tooth stuck between vertebrae in the tail of a herbivorous duck-billed hadrosaur. The specimen was excavated from the Hell Creek Formation, a famous fossil locality in South Dakota.

Scrapes, bites and even dislodged T. rex teeth stuck in the bones of other dinosaur species are common, but there has previously been no way to know whether these bites were made while the prey was being actively attacked by a T. rex, or whether the animal had died in some other way and then been scavenged on by the toothy dinosaur.

Written By: Matt Kaplan
continue to source article at nature.com

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  1. I’d just got used to the idea of T Rex being downgraded from a predator to a scavenger and was expecting the next revelation to be that it was a peace loving lovinghighly trained eastern monk that wandered the desert only using its awesome powers to help others in trouble, and only then right at the end of the programme when all peaceful solutions had failed. Looks like I need to rethink my worldview.

    • In reply to #1 by headswapboy:

      I’d just got used to the idea of T Rex being downgraded from a predator to a scavenger and was expecting the next revelation to be that it was a peace loving lovinghighly trained eastern monk that wandered the desert only using its awesome powers to help others in trouble, and only then right at the end of the programme when all peaceful solutions had failed. Looks like I need to rethink my worldview.

      I think you’ll find that was a Caelifera not a T-Rex … easy mistake.

  2. The T. rex hunter-scavenger debate makes more sense if you conceive of it as a question of to what degree it relied on either method of feeding, not as a categorical either/or issue. Nearly all predators scavenge at some point, and nearly all scavengers kill to eat at some point. There aren’t many animals that can exclusively rely on either lifestyle because A) hunting is a costly activity, whereas scavenging when the opportunity presents itself can easily supplement those costs, but B) scavenging is risky because of potential conflict with nearby predators and because of risks of disease and poison. I think condors and vultures are capable of living as obligate scavengers because any one of them has a broad wing surface area and the ability to rise on thermals and glide tremendous distances. This makes them far more energy efficient when travelling from carcass to carcass.

    Personally, I’ve always thought of the T. rex as being roughly half-hunter and half-scavenger, with its heavy and powerful jaw being specialized for tackling armoured prey like Triceratops and Ankylosaurus, but also for crunching bones and extracting the nutritious marrow inside. It’s interesting that the definitive proof of tyrannosaur hunting should be a hadrosaur bone, and I wonder which species of hadrosaur it was. I also wonder if hadrosaurs could defend themselves against a tyrannosaur with just brute strength as well as by running away, as they don’t seem to have any obvious defences against an attack.

    I also sympathize with Hutchinson later in the article:

    In fact, many palaeontologists are getting fed up with what they consider to be a phony debate over predation and scavenging. “Great galloping lizards!” exclaims John Hutchinson, an evolutionary physiologist at the Royal Veterinary College in London. “It is so frustrating to see provocative half-baked ideas about celebrity species like Tyrannosaurus rex drawing the public’s attention when there is so much more interesting palaeontology to be talking about.”

    There are lots of interesting topics in palaeontology; there are myriad theropod species alone that deserve more public attention, such as the therizinosaurs with their giant claws and herbivorous lifestyles, or the crested oviraptorids which provided some of the earliest evidence for birdlike brooding behaviour. This is before we even talk about the massive sauropodomorphs and the equally diverse ornithiscian dinosaurs and their ancestors, to say nothing of hundreds of thousands of other extinct non-dinosaur species.

    Then again, pop culture hasn’t been kind to palaeontology ever since Crystal Palace Park in London…

  3. This finding shows T Rex went after live prey, but it does not prove it did not also go after carion.

    Further the tooth injury could have happened when T Rex chased away a competitor for a corpse.

    There were some pretty terrifying scavengers. I think the difference we should be looking for is speed. Scavengers don’t have to be good runners.

    • In reply to #5 by Roedy:

      This finding shows T Rex went after live prey, but it does not prove it did not also go after carion.

      Further the tooth injury could have happened when T Rex chased away a competitor for a corpse.

      There were some pretty terrifying scavengers. I think the difference we should be looking for is speed. Scavengers don’t have to be good runners.

      Only if the prey is, in turn, fast. Most of the contemporaries of T. rex weren’t speedy runners either. There’s also the possibility that it relied on a combination of ambush tactics and pack hunting, as the fossils of related species like Daspletosaurus have been found in groups with members of various ages and sizes.

  4. I’d just got used to the idea of T Rex being downgraded from a predator to a scavenger and was expecting the next revelation to be that it was a peace loving lovinghighly trained eastern monk that wandered the desert only using its awesome powers to help others in trouble …

    Well I think some folks who built a certain museum in Kentucky would argue that T-Rex was neither a scavenger nor a predator. T-Rex was most certainly a vegetarian; how else could it co-exist on the ark with all those other animals?

    Snark aside, I never completely bought into the idea that T-Rex was primarily a scavenger. It stands to reason that, when the opportunity presented itself, a T-Rex would not pass up an easy meal, whether it was an animal dead for days or stealing a fresh kill made by some lesser predator, much like the lion does to the hyena. However, with that gigantic maw, fearsome teeth and (apparent) body musculature, I could only think that the T-Rex was a very effective predator in its own right.

  5. Some good observations made here fellow Rdfers.
    I think about shark feeding habits when this debate comes up. We all know they are equal opportunity feeders. Dining on what comes their way, be it live or dead.
    If they can get their mouth around it an in their gut it’s a good day.

  6. In fact, many palaeontologists are getting fed up with what they consider to be a phony debate over predation and scavenging. “Great galloping lizards!” exclaims John Hutchinson, an evolutionary physiologist at the Royal Veterinary College in London. “It is so frustrating to see provocative half-baked ideas about celebrity species like Tyrannosaurus rex drawing the public’s attention when there is so much more interesting palaeontology to be talking about.”

    As other have said, there is no definitive line between scavenging and predation. Many major predators, (eagles, lions, sharks) will scavenge or take kills from other predators when the opportunity arises.

    The more exclusive scavengers are the specialist “tidy-up” squads of Condors, Vultures, etc, who lack the speed or killing capability of the specialist hunters. (leopards. cheetahs, kestrels etc.)

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