Some dinosaurs ate birds

December 6, 2011 • 12:53 pm

Hot off the presses from the Proceedings of the National Academy of Sciences, we have a paper in which a theropod dinosur, Microraptor gui (a feathered dino closely related to the ancestor of modern birds) was found with a bird in its stomach.  M. gui is famous for being a “four-winged” dino that had all four limbs feathered but probably didn’t fly.

I’ll present the results without comment, except for a brief note at the end.

The fossil and schematic diagram (click to enlarge):

Fig. 1. Photograph (A) and line drawing (B) of IVPP V17972A. Anatomical abbreviations: ald, alular digit; cav, caudal vertebrae; cev, cervical vertebrae; den, dentary; fe, femur; fur, furcula; hum, humerus; hy, hyoid bones; ili, ilium; int, integument; isc, ischium; mad, major digit; mid, minor digit; mt, metatarsals; pb, pubis; rad, radius; tb, tibia; thv, thoracic vertebrae; ul, ulna.
Fig. 2. Detail line drawing of stomach contents preserved in IVPP V17972A. Anatomical abbreviation not listed in Fig. 1: tmt, tarsometatarsus. (Scale bar, 10 mm.)

What does it mean?  M. gui probably couldn’t fly (but might have glided), yet it clearly spent time in the trees preying at least partly on flying birds.  This lends some support to the “arboreal” (top-down) scenario for the origin of flight, whereby flight originated from tree-dwelling theropod dinosaurs as a modification of wings used for gliding and controlling descent.  The other hypothesis, the “cursorial” (bottom-up) hypothesis, whereby flight evolved from feathered dinos running on the ground and flapping their proto-wings, perhaps to aid running, jumping and gathering food, isn’t really supported by this paper, but it isn’t ruled out, either.

For more, see the paper here.

34 thoughts on “Some dinosaurs ate birds

  1. Uh, oh. Creationist response: “If birds came from dinosaurs, how come there were still dinosaurs around to eat birds?”

        1. I remember finding a link to a paper on ICR where the paper talked about duck- like, as in the occupied the same ecological niche as ducks. The ICR article said duck-like till about halfway down when it became just duck. I don’t know if I should read Ham’s misinformation or will it just put me in a bad mood all day?

      1. “Christians can’t consistently believe in a fossil record with evidence of animals eating each other and being laid down millions of years before sin—before God said humans and animals were vegetarian and millions of years before God called everything “very good.””

        So you can’t believe in dinosaur fossils that are millions of years old and simultaneously believe in the ‘T-Rex ate coconuts’ story?
        Damn that creationist logic! Foiled again!

      2. “Now how could there be dinosaurs eating birds millions of years before man when the Bible makes it clear that originally all the animals were vegetarian? ”

        hahahahaha

        that’s watertight logic right there! He’s got us dead to rights, boys and girls 🙂

    1. Oh my goodness. The coverage of this story by ICR is perhaps even more insipid. Apparently, Microraptor gui was not a dinosaur at all, but a bird, albeit a very strange bird with four wings. Yes, the feathers on the legs qualify as wings because as we clearly know, only birds have feathers so the back legs must have been wings, and therefore M. gui was just a strange bird and not a theropod. Excuse me while I mop my walls because my head just exploded.

  2. nitpick maybe but as a non-biology guy I’d like clarification: “‘arboreal’ (top-down)” and “‘cursorial’ (top down)”

    Did you mean bottom up for one of those? Or what do you mean by both top down?

  3. If this is a theropod not on the direct line to birds (is this what is called a sister-clade?), then surely all you can infer from this is that this particular theropod was arboreal. Couldn’t it be a specialisation? Or is it just one of example of evidence for the tree-dwelling nature of feathered theropods?

  4. It seems very reasonable to perceive this as supporting the assumption that M.gui was at least intermittently arboreal, but it also seems very plausible that M.gui could have caught this particular dinner on the ground. Tree-loving birds do set down on the ground from time to time, and plenty of non-arboreal carnivores have succeeded in taking advantage of that behavior.

    1. I was about to say the same thing. Future paleontologists will similar bird remains in quite a large number of cat bellies. If they used this kind of reasoning, they’d be very wrong. I think almost all cats get their birds on or near the ground.

    2. well, there’s also the, y’know, wings.
      Future paleontologists won’t be confused by those on their cat fossils.

      I suppose they could have been gliding from low branches to nail ground-foraging birds. But in that case too they were arboreal.

      1. Emu, Ostrich, Kiwi, Penguins etc all have wings but don’t do much flying or hanging around in trees. You can’t infer an arboreal nature from wing-like structures.

        1. *eyeroll*

          Wing-ilke?

          Look at the freaking fossil.
          Now look at the wings of emu, ostrich, kiwi, penguins, etc.

          1. From the article “M. gui probably couldn’t fly (but might have glided)”

            Thats MIGHT have glided. Which is why I referred to them as wing-like, because if they aren’t used to fly, can you seriously call them wings? And they MAY have served another function in this species (display? threat?)

    3. I completely agree and wrote a longish response here-

      The conclusion- “My basic issue with this paper isn’t that it’s wrong, since maybe Microraptor was arboreal and maybe this specimen did kill that bird in a tree. It’s that the paper doesn’t even try to support the various arguments it takes to get to that point. Where’s the data showing scavenged birds are usually disarticulated? Where’s the data showing modern predatory birds usually don’t swallow carcasses head first? Where’s the data showing arboreal birds are usually killed in trees? Nowhere. It’s a neat specimen, but to infer anything more than “Microraptor sometimes ate at least partially articulated enantiornithines head first” is story-telling instead of science, at least at the level of O’Connor et al.’s analysis.”

      1. I agree – insufficient data! How many partially-digested remains have been found in fossilised M. Gui specimens. Enough to make any kind of inference about their habitat. Does anyone know of any other specimens? If not, 1 is a pretty small sample.

  5. Does Microraptor show adaptations for climbing?
    The feathered limbs do suggest gliding, which implies climbing.

    But, even if it definitely does climb, we really don’t know where M. got the bird it ate, do we? May have found it weak or injured on the ground. May have surprised it while it fed on the ground.

    This is certainly interesting, but the usual applies: more research needed. It’s hard to conclude much definite with a sample size of one. More data needed!

  6. Is anyone else bothered by the phrase “a dinosaur that ate birds”? Birds are a subset of dinosaur. Por ejemplo – zebras are a type of mammal; and you wouldn’t call a lion “a mammal that eats zebras”… sounds odd, doesn’t it?

    1. But we’ve had plenty of evidence that zebra were preyed on by other mammals for centuries.

      Direct proof that birds were snacked on by non-avian dinos (though I understand that there’s some debate about Microraptor’s place in that category) hasn’t been found before now.

      1. You missed the cladistic nuances I’m referring to – see, you fixed it by writing ‘other mammals’ and ‘non-avian dinos’. The phrase I have a problem with doesn’t say ‘non-avian dinosaurs’, it just calls them ‘dinosaurs’.

        But since you naturally modified ‘mammals’ and ‘dinosaur’ to specifically distinguish them from their subsets; I can tell you share my view. 🙂

    2. I had the same response.

      Yes, obviously some dinosaurs ate birds. Dinosaurs *still* eat birds. We’ve known about peregrine falcons for how many centuries? This is not news. 🙂

  7. Interesting article.

    But, I would like to know … what is my take away from the article? Did birds start flying from the ground up? Or trees down?

    Wayne

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