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10 Clawed Facts About Therizinosaurus

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If T. rex is the Citizen Kane of dinosaurs, Therizinosaurus and its kin are The Rocky Horror Picture Show: They’re strange-looking, slightly threatening, and command a dedicated fan base. Here’s some trivia guaranteed to impress your fossil-loving amigos.

1. Therizinosaurus Had the Longest Claws of Any Known Animal

The humongous claws on this dino’s hands were capable of reaching well over two feet in length. Appropriately, its name literally means “scythe lizard.”

2. Despite This, it Was (Probably) An Herbivore

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With fingers that seemingly belong in a slasher flick, you’d think these creatures were designed to slice and dice hapless victims. But most of its relatives had small, leaf-shaped teeth built to munch on foliage. (Scientists have yet to uncover a Therizinosaurus skull.) So what’s with those frightening digits? The theory is that, come mealtime, they might have helped the dinos pull down lush tree branches. For a cooler explanation, skip ahead to bullet point number nine.

3. Therizinosaurus Was Originally Mistaken for a Huge, Turtle-Like Reptile.

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In 1954, Russian paleontologist Evgeny Aleksandrovich Malayev concluded that the beast basically resembled a modern sea turtle. He wrote that its distinctive forelimbs were in fact “powerful swimming organs” with claws designed for “cutting aquatic vegetation.”

4. It’s Part of a Formerly-Baffling Family.

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When it became clear that these things were actually dinosaurs, scientists didn’t initially know how to classify the eccentric Therizinosaurids. Could they be related to the gigantic, long-necked sauropods like Jurassic Park’s Brachiosaurus? Or did they belong to the "bird-hipped" order of dinosaurs along with Stegosaurus and Triceratops?

Despite their plant-guzzling habits, closer examination revealed that therizinosaurs hailed from a group known as theropods, the vast majority of which (Tyrannosaurus, Velociraptor, etc.) were carnivores. Strange as this might sound, today’s pandas (which only occasionally eat meat) are similarly considered members of the mammalian "carnivora" order.

5. Some Therizinosaurs Were Covered in Feathers.

Danny Cicchetti

China’s Beipiaosaurus had multiple layers of primitive feathers, as seen in some beautifully-preserved fossils. Given its limb proportions, Beipiaosaurus definitely didn’t fly, so this plumage likely served to keep it warm and attract the opposite sex.

6. A Nest of Therizinosaur Eggs Was Found in 2013.

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After locating 17 clutches of dinosaur eggs in the Gobi Desert, Hokkaido University’s Yoshitsugu Kobayashi concluded that they’d been laid by indigenous therizinosaurs, a few bony remains of which had been unearthed nearby. If true, this would imply that the animals were somewhat social (at least, come nesting season).

7. Therizinosaurs Had Weird Feet.

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Ever the nonconformists, therizinosaur feet rested on four toes while standing and walking. Most theropods, meanwhile, only used three.

8. Therizinosaurus Was One Hefty Dino.

Scott Hartman

Let’s return to Therizinosaurus itself, shall we? The red areas in the above picture represent all of its presently-known skeletal material (the rest has yet to be found). Based on these partial remains, scientists have ascertained that the critter’s total length was somewhere in the ballpark of 10 meters (33 feet) while it could’ve weighed upwards of 5 tons. Not too shabby…

9. Therizinosaurus Had to Cope With a Huge T. rex Cousin.

Tarbosaurus bataar and Tyrannosaurus rex are so similar that they may have belonged to the same genus (though most experts disregard that idea). The former predator occupied Therizinosaurus’ Mongolian range roughly 70 million years ago, making this herbivore’s fearsome claws look all the more necessary. Here’s a cool (Greek language) clip from 2002’s Chased by Dinosaurs documentary in which these natural enemies spectacularly square off.

10. There’s a Life-Sized Therizinosaurus Statue in Poland.

Alina Zienowicz

Jurapark, located in the village of Bałtów, contains dozens of full-scale dinosaur models, including Allosaurus, Diplodocus, and the world-famous Iguanodon.

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CHLOE EFFRON / DINOSAURS: ISTOCK
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science
Why Are There No More Dinosaurs?
CHLOE EFFRON / DINOSAURS: ISTOCK
CHLOE EFFRON / DINOSAURS: ISTOCK

WHY? is our attempt to answer all the questions every little kid asks. Do you have a question? Send it to why@mentalfloss.com.

Actually, there are still dinosaurs: Birds! But let’s talk about that a little later. Scientists have found clues in rocks and fossils that tell us that by 65 million years ago, the climate (CLY-met), or usual weather, of the Earth had changed a lot, becoming cooler and drier. That was hard on the heat-loving dinosaurs. But that’s not why almost all of the dinosaurs became extinct, or disappeared forever. Scientists think a terrible event occurred that killed them off.

In 1991, scientists discovered a huge 110-mile-long crater, or hole, in the Gulf of Mexico. They think this crater was made by a giant, fiery, 6-mile-wide asteroid (AST-er-oyd) from space that smashed into the Earth about 65 million years ago. The impact was more powerful than any bomb we have ever known. Scientists believe this event killed most plant and animal life—including the dinosaurs. The asteroid probably caused shockwaves, earthquakes, fireballs, wildfires, and tidal, or really big, waves. It also sent huge amounts of dust and gas into the atmosphere, which is like a big blanket of air that surrounds the Earth. That was really bad for the planet.

The dust blocked sunlight, making the planet very cold and dark. Then, over time, the gases trapped heat, causing the Earth to get even hotter than it was before the asteroid hit. This change was deadly for most dinosaurs, and they became extinct. But birds survived. Many millions of years earlier, they had evolved (ee-VOL-ved), or changed slowly over time, from one group of dinosaurs. And when the dinosaurs disappeared, mammals diversified (die-VERSE-uh-fide), or changed, into many different kinds of animals—including us, many millions of years later. So the next time you see a bird swoop by, wave hello to the little flying dinosaur!    


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Creative Beasts
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Animals
These Scientifically Accurate Dinosaur Toys Are Ready to Rule Your Desk
Creative Beasts
Creative Beasts

In May 2016, we told you about Beasts of the Mesozoic, a line of Kickstarter-backed dinosaur toys that would reflect the feathery truth about the mighty beasts and provide an alternative to the Hollywood-enhanced glamour of the Jurassic Park franchise.

Then, absolutely nothing happened. Having being fully funded on the crowd-sourced platform, Beasts seemed to be mired in production issues. Now, nearly two years after designer David Silva announced the project, the toys are finally ready to hit shelves.

A Beasts of the Mesozoic action figure in retail packaging
Creative Beasts

The Beasts line will initially consist of 11 figures due to ship this month, with six more expected to arrive in May. Included in the first wave are Velociraptor mongoliensis, Atrociraptor marshalli, Balaur bondoc, Dromaeosaurus albertensis, Zhenyuanlong suni, Pyroraptor olympus, Linheraptor exquisitus, Velociraptor osmolskae (red), FC (Fan’s Choice) Dromaeosaurus albertensis, FC Pyroraptor olympus, and FC Zhenyuanlong suni.

In his updates, Silva said the delay was due in large part to how quickly the scope of the line grew. At the time the campaign started, he was planning on just three figures that would ship by May 2017. By the end, he had 25 items, including accessory packs.

You can pre-order the first wave ($35 to $40 each) at BackerKit.

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