Dromaeosaurus

About Dromaeosaurus

Features and Discovery History

Dromaeosaurus was a medium-sized theropod that lived on the North American continent during the Late Cretaceous period (approximately 80 to 69 million years ago). Its name derives from the Greek for "running lizard," and it is known as a representative dinosaur of the Maniraptora and Dromaeosauridae families, collectively referred to as "raptors."

The first fossils were discovered in 1914 by Barnum Brown and others from the American Museum of Natural History along the Red Deer River in Alberta, Canada (now Dinosaur Provincial Park).

When first described in 1922, Dromaeosaurus was classified as a member of the "Deinodontidae (now Tyrannosauridae)" family. Because its front teeth were large and its snout was deep and structurally robust, it was thought to be a small tyrannosaurid.
However, the situation changed dramatically in 1969 when John Ostrom studied and described Deinonychus. Many commonalities with Deinonychus and Velociraptor, such as the large, sickle-shaped claw on the foot (sickle claw) and long forelimbs, were found, leading to the establishment of a new, independent group called "Dromaeosauridae."

Although fossilized feathers of Dromaeosaurus itself have not been found, evidence from closely related species (such as quill knobs on the ulna) suggests its entire body was covered in feathers. While it could not fly, its wing-like forelimbs likely helped maintain body temperature, served for display, and assisted in balancing while running.

Furthermore, analysis of its braincase (the bony cavity containing the brain) reveals that Dromaeosaurus possessed high intelligence, with particularly well-developed senses of smell and stereoscopic vision. It is believed to have been an excellent diurnal hunter.

Its Greatest Weapon: The Powerful "Jaw"

Generally, when one hears "raptor," they might imagine it slashing its prey with the giant, sickle-like claw (sickle claw) on the second digit of its hind foot. However, recent biomechanical research (RPR model) suggests that this claw was likely not used for slashing, but rather as an anchor to pin prey to the ground and prevent it from escaping, similar to modern birds of prey.

Dromaeosaurus's most formidable weapon was its powerful "jaw," generated from its unique skull structure. The skull featured a highly raised "sagittal crest," to which strong muscles for closing the jaw were attached. Because of this, it is estimated that Dromaeosaurus's maximum bite force reached roughly three times that of a similarly sized Velociraptor.

While they had fewer teeth, the roots were thick and sturdy. It is believed they employed a "puncture and pull" predatory behavior, similar to Tyrannosaurus, biting deeply into prey and using their neck muscles to tear chunks of flesh backward. The severe wear observed on fossilized teeth also suggests they may have crushed prey along with their bones.

Classification and Evolution of Gigantism

In the past, it was thought that multiple species existed within the genus Dromaeosaurus. However, due to fossils being too fragmentary or being reclassified into other genera, as of 2024, only the originally described type species, Dromaeosaurus albertensis, is recognized as a definitively valid species.

Dromaeosaurus's weight is calculated to be around 15-16kg. However, some studies estimate it could have reached up to approximately 34kg.

The number of Dromaeosaurus fossils discovered in the Dinosaur Park Formation is very small, and it is extremely rare compared to Saurornitholestes, which lived in the same area. This leads to speculation that Dromaeosaurus either required a vast territory to hunt large prey or lived deep in forests where fossils are less likely to be preserved.

Dromaeosaurus Stamp and Fossil Gallery