Utahraptor vs. Iguanodon - Who Wins?

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Utahraptor vs. Iguanodon

Side profile of two utahraptors fighting
DEA PICTURE LIBRARY/Getty Images

When it comes to dinosaur-on-dinosaur combat, the early Cretaceous period (about 144 to 120 million years ago) offers relatively slim pickings. We know the earth's continents must have been thick with dinosaurs during this time; the trouble is, their fossils are relatively rare, especially compared to the late Jurassic and late Cretaceous periods. Still, Dinosaur Death Duel enthusiasts need not despair: we know for a fact that the habitats of the large, terrifying Utahraptor and the even larger, but much less terrifying, Iguanodon overlapped in North America for millions of years. The question is, could a hungry Utahraptor have taken down a single, full-grown Iguanodon?

In the Near Corner: Utahraptor, the Early Cretaceous Killer

Velociraptor gets all the attention, but this forty-pound predator was a mere rounding error compared to its much bigger ancestor--adult Utahraptors weighed in the vicinity of a half to three-quarters of a ton. (What about Gigantoraptor and Megaraptor, you may ask? Well, despite their impressive names, these theropod dinosaurs weren't technically raptors, which still leaves Utahraptor at the top of the heap.)

Advantages. Like other raptors, Utahraptor was equipped with single, huge, curving claws on each of its hind feet--except that in Utahraptor's case, these claws measured up to nine inches long, about the same size as a Saber-Toothed Tiger's canines. Also like other raptors, Utahraptor was endowed with an active, warm-blooded metabolism, and probably hunted in packs. Put two and two together, and you get a lithe, speedy, smarter-than-average predator that slashed at its prey mercilessly with its scimitar-like claws.

Disadvantages. It's hard to identify a weak spot in Utahraptor's arsenal unless it was its presumed coat of feathers, which exposed it to the ridicule of other dinosaurs. However, it may be a telling clue that the raptors of the late Cretaceous period were much smaller than Utahraptor, a reversal of the usual evolutionary pattern (in which pint-size progenitors progress to much bigger descendants millions of years down the road). Might Utahraptor's size, and metabolic requirements have been a hindrance rather than a help?

 

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Utahraptor vs. Iguanodon

Iguanodon dinosaur roaring while surrounded by ferns, cycas and wollemia plants.
Elena Duvernay/Stocktrek Images/Getty Images

In the Far Corner - Iguanodon, the Humble Herb-Nibbler

Only the second dinosaur in history ever to receive a name, Iguanodon is also the fuzziest in the public imagination, a gray, shapeless, vaguely repulsive-looking ornithopod that invites comparison to the modern Wildebeest (aka "the Box Lunch of the Serengeti"). It doesn't help that Iguanodon was continually being reexamined, reimagined and reconstructed for the first hundred or so years after its discovery, further testing the average dinosaur-lover's patience.

Advantages. Although it was far from the biggest plant-eating dinosaur of the early Cretaceous period, Iguanodon achieved a respectable weight of about three tons--yet it could still rear up on its hind legs and run away if circumstances demanded. There's also some evidence that Iguanodon roamed North America in herds, which would have afforded it some protection from predators. As for those characteristic spikes on each of Iguanodon's thumbs, they probably wouldn't have been much use in battle, though they might have given an unusually dim theropod second thoughts.

Disadvantages. As a general rule, herbivorous dinosaurs weren't the smartest animals to roam the face of the earth--and Iguanodon seems to have been even dumber than the norm, only a bit more intelligent than an eggplant. As mentioned above, virtually the only weapons Iguanodon had in its defensive arsenal were a) the ability to run away and b) those dangerous-looking thumb spikes, the true purpose of which remains a mystery to this day. Otherwise, this ornithopod was the Mesozoic equivalent of a sitting duck.

Fight!

Let's tilt the odds in the underdog's favor, and suppose that a single, hungry Utahraptor has taken it upon itself to stalk a small herd of three or four full-grown Iguanodons. Sensing danger, the Iguanodons huddle closer together, then rear up on their hind legs and run as fast as they can toward some dense undergrowth. Inevitably, one of the herd is pokier than the rest--remember the punchline of that old joke, "I don't have to run faster than the bear, I just have to run faster than you?"--and the Utahraptor makes its move. The theropod coils back on its muscular hind legs and executes an Olympic-class long jump, landing on the lagging Iguanodon with its huge hind claws.

And the Winner Is...

Do we even need to say it? Pitifully, the Iguanodon twists around and flails its forelimbs at the attacking Utahraptor, attempting to blind the predator with its thumb spikes (not an optimistic prospect, since Iguanodon's cold-blooded metabolism, combined with its small brain, make a swift, targeted counterattack extremely unlikely). The Utahraptor hacks away with its hind claws at Iguanodon's belly, inflicting a series of deep wounds that quickly bring the larger ornithopod crashing to the ground. Before the unfortunate Iguanodon has even breathed its last, Utahraptor tucks in for its meal, starting with the layers of muscle and fat lining Iguanodon's capacious stomach.