The first of the dromaeosaurs to be discovered, Dromaeosaurus, was about the size of a large dog. Its jaws were long and solidly built for its size, and its neck was curved and flexible. It may have been able to smell its prey, and it probably possessed a good sense of hearing. Its tail was sheathed in a lattice of bony rods but was flexible at the base, allowing it to be carried in a sharply upturned aerial like position. Its remarkably large eyes gave it excellent vision. Its vicious sickle like claws, although shorter than those of other dromaeosaurs, still gave it a distinct advantage over most of its prey.

The first and only good Dromaeosaurus remains were found by Barnum Brown on the south bank of the Red Deer River in 1914. Several later discoveries disclosed Dromaeosaurus teeth among the bones of much larger dinosaurs. This led to speculation that dromaeosaurs attacked larger animals, but the teeth may simply have washed into the site.

Dromaeosaurus seems to have become extinct about 70 million years ago, well before the Cretaceous Tertiary Boundary