Utahraptor

Utahraptor was a colossal dromaeosaurid theropod that inhabited North America during the Early Cretaceous epoch. Far larger and more heavily built than gracile relatives like Velociraptor, it rivalled large modern bears in overall body mass. Its bones were thick and robust, indicating that it relied on sheer strength and ambush tactics rather than blistering foot speed. The sickle claws on its second toes were enormous and exceptionally deep, ideal for piercing and gripping large herbivorous prey. A massive quicksand fossil block discovered in eastern Utah preserves multiple individuals of various ages, suggesting they may have gathered together or hunted in social groups. Though direct integument impressions have not yet been recovered, its evolutionary position within dromaeosaurs indicates it was likely covered in filamentous plumage.

Its sickle claw measured over twenty centimetres along the inner curve, making it the largest of any known dromaeosaur.

Where and when

Utahraptor lived in the Early Cretaceous, from 139 to 134 million years ago (Valanginian age). Its remains come from United States, in the Cedar Mountain Formation.

The numbers

Length 5.5 m (estimates run from 5 to 6 m). Mass about 370 kg. Hip height about 1.5 m. That is 3.2 human-lengths, or 0.49 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, hip height.

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