10 Dinosaur Controversies That Just Won't Go Away

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Want to Upset a Paleontologist? Ask Her if T. Rex Had Feathers

T. rex and triceratops
An encounter between T. Rex and Triceratops (Alain Beneteau).

You might think that, by now, biologists, geologists and paleontologists have figured out everything there is to know about dinosaurs. But you'd be dead wrong: while there's consensus about most issues, there are still dissenting voices, and other controversies divide the experts into equally sized camps. (And, too, certain segments of the general public continue to debate issues, like whether dinosaurs really existed, that have long since been resolved!) On the following pages, you'll find 10 dinosaur controversies guaranteed to provoke arguments with your spouse, your kids, or your fellow workers.

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Were Dinosaurs Warm-Blooded?

Afrovenator (Wikimedia Commons).

Cold-blooded animals warm themselves in the sunlight, and radiate away excess heat at night. Warm-blooded animals generate their own internal body heat, and are thus more agile and energetic. Where did dinosaurs lie on this spectrum? Most paleontologists believe that theropods (the family of dinosaurs that includes raptors and tyrannosaurs) were warm-blooded, but the jury is still out on large, plant-eating hadrosaurs and sauropods, for which an endothermic metabolism presents technical difficulties. For more on this contentious issue, see Were Dinosaurs Warm-Blooded?

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Did Birds Evolve from Dinosaurs?

Iberomesornis (Wikimedia Commons).

In a way (if you'll excuse our mixing of animal metaphors) to ask whether birds evolved from dinosaurs is a red herring: the vast majority of working scientists accept the bird-dinosaur link, and the few iconoclasts are rightly rejected as cranks. What's at issue here is not whether, but when, birds evolved from dinosaurs: this may have happened multiple times during the Mesozoic Era, and only one of those lineages went on to spawn modern birds. And here's a related controversy: did the first proto-birds learn to fly by falling out of trees, or taking off from a Jurassic runway?

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How Did Dinosaurs Have Sex?

tyrannosaurus rex
Is this how Tyrannosaurus Rex had sex? (Mario Modesto).

Since no species have been fossilized in flagrante delicto (though ask us some time about the prehistoric turtle Allaeochelys), we can't say for sure how dinosaurs had sex--or even if they possessed the Cretaceous equivalent of penises and vaginas. Our lack of knowledge is especially vexing when it comes to multi-ton behemoths like Apatosaurus and Shantungosaurus, since there are no modern animals (apart from elephants and giraffes, which are an order of magnitude smaller) for which we can draw a convincing parallel. For more on this salacious subject, see How Did Dinosaurs Have Sex?

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Can We Clone a Dinosaur?

Universal Pictures

It seems so simple, right? Just find a hundred-million-year-old mosquito encased in amber, extract the blood it recently sucked out of a Spinosaurus, and unfurl the genetic blueprint of the world's largest terrestrial predator. The sad fact is, though, that DNA is an extremely fragile molecule, and tends to degrade irreparably after thousands, much less tens of millions, of years. But while most paleontologists (with the possible exception of Jack Horner) agree that  cloning a dinosaur is out of the question, the same may not be true of the much more recent Woolly Mammoth, numerous specimens of which have been preserved in permafrost.

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Did All Tyrannosaurs Have Feathers?

Yutyrannus (Nobu Tamura).

The mighty tyrannosaurs are under siege: first came the discovery of a small, ancestral Chinese tyrannosaur, Dilong, that was covered with feathers, and next, the more recent discovery of the plushly tufted, two-ton Yutyrannus. The obvious question presents itself: were these two tyrannosaurs unique, or did all members of the breed (including the biggest, fiercest tyrannosaur of them all, Tyrannosaurus Rex) sport feathers at some stage in their life cycles? Experts disagree, though one suspects some of them are overly wedded to the green, scaly-skinned T. Rex that attracted them to paleontology in the first place!

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Is There Really Such a Thing as a Brontosaurus?

Apatosaurus (Carnegie Museum of Natural History).

For over a century, Brontosaurus was one of the world's most famous dinosaurs, second in popularity only to T. Rex (and perhaps Triceratops). Then, a kerfuffle over this dinosaur's "type specimen" caused it to be rechristened Apatosaurus, the name by which millions of kids know it today. Recently, a team of paleontologists announced that Brontosaurus deserves its own genus after all (alongside, not replacing, Apatosaurus), but not all of their colleagues are convinced. It might take a few years for the controversy over Brontosaurus to resolve itself, at which point the official dinosaur record books may well look very different.

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Were Some Dinosaurs "Growth Stages" of Other Dinosaurs?

Torosaurus, which may actually have been Triceratops (Carnegie Museum of Natural History).

In 2010, the famous paleontologist Jack Horner (who still thinks we can clone a dinosaur; see slide #5) announced that the dinosaur we know as Dracorex was actually a juvenile Pachycephalosaurus; a few years later, he repeated this trick, claiming that Torosaurus was an exceptionally old Triceratops individual. We don't yet know where the truth lies, but the fact is that an awful lot of dinosaur genera closely resemble one another, and there's still a lot we have yet to learn about the growth stages of ceratopsians, sauropods, and other kinds of dinosaurs. So don't be surprised if some very familiar dinosaurs disappear by the time your kids graduate from high school!

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Could Some Dinosaurs Have Survived the K/T Extinction?

K/T meteor
An artist's impression of the K/T meteor impact (NASA).

The K/T meteor impact, 65 million years ago, wiped out all of the world's dinosaurs, as well as their pterosaur and marine reptile cousins. But isn't it just barely conceivable that one obscure family of dinosaurs, sheltered in an island or valley who-knows-where, managed to escape destruction and survive down to the present day? That's the story subscribed to by cryptozoologists, who love to speculate that the Loch Ness Monster is actually an Elasmosaurus or the mythical African beast Mokele-mbembe is a living, breathing Diplodocus. No reputable scientists believe any of this; you can gauge the general public's views with a quick Google search.

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How Did Sauropods Hold Their Necks?

The long-necked sauropod Mamenchisaurus (Sergey Krasovskiy).

This nuts-and-bolts controversy may seem arcane, but it has a direct bearing on the first item on this list, whether or not dinosaurs were warm-blooded. While it's standard practice to depict the likes of Apatosaurus and Brachiosaurus as holding their heads up to the fullest height possible, some paleontologists insist that this would have placed an intolerable burden on these dinosaur's hearts, which would have to pump blood 30 or 40 feet vertically. The only way to pull off this trick, the argument goes, is with a warm-blooded metabolism; the trouble is, a warm-blooded, 20-ton Diplodocus would cook itself from the inside out! The argument rages on.

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Did Dinosaurs Even Exist?

This may seem like a no-brainer, but if you've ever seen the parody website Christians Against Dinosaurs, you know there's a segment of the U.S. population that insists dinosaurs are a secular myth. And even many fundamentalist Christians who accept the existence of dinosaurs argue that these creatures lived only 6,000 years ago, since that's when the Bible says the world was created. It's sad to think that words are still being expended on this argument--and on supposedly "scientific" frauds like Intelligent Design--but we'd be remiss if we didn't include it in this slideshow.