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Deinocheirus Revisited

It’s funny what sticks in your mind.

As a kid I had the standard kid-type obsession with dinosaurs. Having an obsession with dinosaurs is great, or at least it was great in my case, because it mostly manifested itself as a desire to read every dinosaur book on which I could lay my sticky kid paws, and books were the one thing I could reliably convince my mom, bless her intellectual-curiosity-fostering heart, to buy.

One of these books—and it was one of the better, more modern ones, where the Tyrannosaurus’s tail didn’t drag on the ground—had a description of a Deinocheirus (i.e., D. mirificus), which was a theropod1 with these giant, terrifying arms and hands with articulated wrists. The hands therefore could rotate and turn toward each other. The book explained this so memorably I remember the sentence verbatim even now, 20 years later:

It might have been able to catch a ball, if anyone had been there and had dared to throw one.


I wrote the above paragraphs over ten years ago. In the intervening time, research on D. mirificus has revealed2 that it was a much less obvious animal than its description when the ball-catching sentence was written had it. It was first identified by a partial skeleton that revealed only its enormous, clawed forelimbs, and was assumed a predator. Later complete skeletons revealed a duck bill and evidence for anatomic adaptation to dredging vegetation from its swampy habitat.

Deinocheirus was a six-ton duckish herbivore that used its gigantic mitts to rake through the swamp goop it must have eaten in absolutely vast quantities. If you'd “dared to throw” a ball at it, it would have blinked at you, then gone back to raking goop.

It's funny what sticks in your mind; it's funnier still that what sticks in your mind often bears as much resemblence to the facts as our first conception of D. mirificus as a dextrously terrifying predator did to the pond weed-eating reality3.


  1. Note that the Theropoda sub-order contains most of the really badass carnivores that small-framed, owl-eyed youngsters like yours truly were by turns fascinated with and terrified by.
  2. Full disclosure: I, like many other people, only updated my knowledge of Deinocheirus thanks to the exquisitely-made Prehistoric Planet series.
  3. As a final twist of the knife, it turns out I'd also been misspelling and mispronouncing “Deinocheirus” until literally yesterday.