try this site Name Meaning: Utah Thief Geologic Era: Early Cretaceous Location Found: Utah

page Estimated Range: Western North America

Size: Up to seven meters in length

Extinction: 126 million years ago

Pictured below is a cast of one of the fingers of Utahraptor. To get an idea of the size of this structure, notice that my fingers are holding the specimen on the far left of the image. Utahraptor was one of the largest dromaeosaurs. In life, the claw would have been covered with a keratin sheath (similar to the material in your fingernails) which would have made it longer and sharper.

Dromaeosaurs are usually characterized as being fast moving animals, but Utahraptor would have been an exception. Its bones show that it was not an especially fast moving predator, but what it lacked in speed, it made up for in power. Unlike its smaller relatives, who likely relied on their claws, Utahraptor’s primary weapon would have been its mouth. The jaws of Utahraptor were much stronger than average for a dromaeosaur, and were well equipped for delivering powerful bites. In terms of mass, Utahraptor would have been comparable to a modern polar bear, and likely went after prey somewhat larger than itself.

It is possible that Utahraptor hunted in packs, or at least family units. Hunting in a group would have made the odds of a successful kill much higher, and would allow for individuals to look after one another should an injury occur. There is no direct evidence yet for the pack hunting idea, but Utahraptor remains of several animals of varying ages were found together. It is also possible, however, that these remains were deposited separately, perhaps being drawn to a predator trap such as quicksand. It is thought that Deinonychus, a smaller relative, hunted in groups or mobs, so the possibility is certainly there. Like other dromaeosaurs, Utahraptor was most likely covered in feathers, as the earliest dromaeosaurs from the Jurassic show this trait. Very late dromaeosaurs were feathered as well, so there is no reason to think this trait would have just disappeared.

Image Credits:

Life Restoration: Von Ferahgo the Assassin (Emily Willoughby, – Eigenes Werk, CC BY-SA 3.0,

Skeleton: Von Zach Tirrell from Plymouth, USA – Utahraptor, CC BY-SA 2.0,