Utahraptor

## Physiology

### Attributes

Large size; serrated teeth; 12 inch sickle claw; large talons and claws; largest dromaeosaur

## Biography

### Time

130 to 100 MYA

> *The most terrifying creature on Earth: Utahraptor, a giant, carnivorous super-sized raptor. Agile, athletic, and with lethal, razor-sharp claws, this seven-meter pack-hunting killer is well-armed. And long fingers help them to latch on to swift-moving larger prey.*
>
> Narrator, describing *Utahraptor*, Land Hawks

***Utahraptor*** (name meaning "*Utah Thief*") is a genus of dromaeosaurid dinosaur that originated during the Early Cretaceous period in what is now North America. Measuring 7 meters long, standing 2 meters tall, and weighing almost 700 kilos, *Utahraptor* was the largest raptor ever discovered, much larger than its later kin, such as *Deinonychus* and the more famous *Velociraptor*. Indubitably the most terrifying creature of all, the size of this monstrous raptor was enough to enable the potential to attack even small sauropods.

In the episode "*Land Hawks*," a pack of seven *Utahraptors* were hunting for prey from Early Cretaceous North America, 127 million years ago.

## Facts

### Era & Discovery

*Utahraptor* was not only the largest but also the oldest known dromaeosaur. Thus, it was the first raptor ever to evolve. It lived in North America during the Early and throughout the Middle Cretaceous period from 130 – 100 million years ago and was one of the apex predators of its time and region. It shared its environment with other creatures like *Acrocanthosaurus*, *Deinonychus*, *Iguanodon*, *Polacanthus*, *Pteranodon*, and *Ornithocheirus*.

Hence its name, the first specimens of *Utahraptor* were found in 1975 by Jim Jensen in the Dalton Wells Quarry in east-central Utah, near the town of Moab, but did not receive much attention at the time. About 15 years later, after a find of a large foot-claw by Carl Limoni in October 1991, James Kirkland, Robert Gaston, and Donald Burge uncovered further remains of *Utahraptor* in 1991 in the Gaston Quarry in Grand County, Utah, within the Yellow Cat and Poison Strip members of the Cedar Mountain Formation. Therefore, *Utahraptor* is known from a well-preserved skeleton found in 1991 in Utah, USA and fragmentary remains from South America.

### Physical Attributes

A species of dromaeosaur notable by its enormous size, *Utahraptor* stood 6 – 8 feet (2 – 2.4 m) tall, measured 16.5 – 24 feet (5 – 7.3 m) in length, and weighed in at over 500 – 680 kg (1,100 – 1,500 lbs.), comparable in size to a large bear. This makes *Utahraptor* arguably the largest and strongest dromaeosaur that ever existed. *Utahraptor* had large eyes with excellent vision that allowed them to see in the dark, self-replenishing teeth in its jaws, and long grasping hands with large, sharp ripping claws.

   Its toe joints were specially enlarged so that its massive sickle-like claw could be raised upward and backward to avoid damage while running. The unique wrist-joints of *Utahraptor* allowed the hands to pivot sideways, an action similar to the folding of a bird's wing. But when used in an attack, swinging in a wide arc, its huge, 9 – 15 inch (22 – 38 cm) slashing claw flexed forward as the animal kicked out would produce terrible wounds enabling *Utahraptor* to cripple and kill animals much larger than itself. With lethal claws, these killers were well-armed, and long fingers allowed them to latch onto swift-moving, larger prey.

*Utahraptor's* body build is muscular, but relatively slim and lean, fitting their consistently active lifestyle. Although a very fast, agile, and flexible theropod dinosaur, able to reach speeds of up to 20 – 28 mph (32 – 45 km/h) and leap an amazing 15 feet (4.7 m) into the air, *Utahraptor*, however, had the short legs of a sprinter and did not pursue its prey for long. Despite its large size, *Utahraptor* could crouch down to the ground, which gave it the ability to use even the slightest cover if needed. Without being seen, it could peer over cover while remaining hidden.

### Behavior & Traits

Undoubtedly the most terrifying creature that ever walked the earth, *Utahraptor* was an extremely aggressive, very cunning, and highly intelligent theropod dinosaur, being able to ambush, startle, and then attack their prey, despite being small-sized in comparison to most other dinosaurs. Like many predatory dinosaurs and all species of raptors, even *Utahraptor* was a social dinosaur that lived and hunted in packs; in numbers from a minimum of 3 to as many as 12 individuals in a single pack, from full-grown adults to assorted young.

Lead by Alpha, *Utahraptor* lived in jungles, open grasslands, and alpine environments, as the thick forests and rocks provide cover for them and nests for their young. *Utahraptor* nests were dug out amid the roots of giant jungle trees. All chicks were the responsibility of the entire pack, who brought back food for the young. While out hunting, a single guard or even two would remain behind, watching over the nest.

*Utahraptor* was a deadly and vicious predator, able to quickly and brutally kill their prey. Their hunting territories were large and well-marked, with a mixture of tree scrapings, urine, feces, and the like. Surprisingly, *Utahraptor* would sometimes conceal themselves for an ambush by burying themselves in rubble in the area.

When hunting, *Utahraptor* preferred to stalk and follow their prey unseen under the cover of vegetation and/or darkness, before emerging from their cover and swiftly closing in for the kill. They would ambush their prey, getting as close as possible before bursting out of cover and chasing down its prey. They were very efficient at using the terrain of their region to their advantage and would chase prey into canyons or over low cliffs.

They also had a hard time going without a kill for more than a week. Whenever they made a kill, they ate as much as 100 kilograms in each sitting. Whenever they ate, there was a strict pecking order in their feasts, and the large adults come first, whereas the younger and weaker *Utahraptors* would be nearby and have to wait their turn. Because of their large size, *Utahraptor* hunted anything from animals as small as *Hypsilophodon* to even small sauropods.

## Trivia

* *Utahraptor* is the largest dromaeosaur to be introduced to the museum.
* *Utahraptor* has often been credited as the most terrifying creature that ever walked the Earth.
* The sound effects of Utahraptor are that of cougar and leopard sound effects, as well as the sounds of the Venatosaurus from Peter Jackson's King Kong game and the Dilophosaurus sounds from the PS3 video game Turok. They also produce an unknown screaming sound effect.
* *Utahraptor*is now known to have feathers.