Utahraptor, meaning “Utah’s predator,” was a significant predatory dinosaur from the Early Cretaceous period, 139 to 135 million years ago. This formidable creature belongs to the dromaeosaurid family, a group recognized for their distinctive sickle-shaped claws. Its discovery marked a unique moment in paleontology, challenging previous understandings of raptor size and distribution. Found primarily in the Cedar Mountain Formation of Utah, this dinosaur holds a special place in the fossil record.
Key Dimensions
Utahraptor was a substantial predator, with estimates placing its length between 6 to 7 meters (20 to 23 feet). Its estimated standing height at the hip ranged from 1.5 to 1.8 meters (5 to 6 feet), with total height up to 2.1 meters (7 feet).
Weight estimates for Utahraptor vary. Many estimations suggest a weight of less than 500 kilograms (1,100 pounds). Some authors have proposed a range of 250 to 350 kilograms (550 to 770 pounds), while more recent studies from 2024 indicate certain large specimens could have weighed around 777 kilograms (1,713 pounds).
Contextualizing Its Size
Utahraptor was considerably larger than some of its more famous dromaeosaurid relatives. For instance, Velociraptor, which lived much later, was turkey-sized, standing only about 0.5 to 0.7 meters tall and weighing around 15 to 23 kilograms (33 to 50 pounds). Utahraptor dwarfed Velociraptor, with their foot sizes alone showing a difference akin to a fox and a bear. It was also approximately twice the size of Deinonychus, another prominent dromaeosaurid, which measured around 4 meters (13 feet) long and weighed about 100 kilograms (220 pounds).
Comparing Utahraptor to modern animals, its weight was comparable to that of a polar bear or a large grizzly bear. An adult Utahraptor would have stood significantly taller than an average human, with its hip height often exceeding human height. Its imposing dimensions set it apart within the “raptor” family.
Physical Attributes Linked to Size
Utahraptor’s large size influenced its overall physical characteristics, resulting in a notably robust build. Unlike the more slender depictions of some other dromaeosaurids, Utahraptor possessed a heavily built, barrel-chested body with limb bones that were considerably more massive than those of similarly sized theropods. This bulkiness suggests it was not designed for swift, sustained pursuit, instead favoring an ambush hunting strategy. Its thick leg bones indicate substantial leg force, allowing it to deliver powerful blows.
A prominent feature directly related to its size was its formidable sickle claw on the second toe of each foot. The bony core of this claw measured an estimated 22 to 24 centimeters (8.7 to 9.5 inches), and with a keratin sheath, it could have reached up to 38 centimeters (15 inches) in length. This large claw was likely used for piercing, holding, and dispatching prey. Its robust build and powerful limbs would have enabled it to effectively pin down and subdue larger animals, making its claws particularly effective tools. Utahraptor also had serrated teeth, suggesting a significant role for its jaws in processing its catches.