The Herrerasaurus is one of the oldest predatory dinosaurs known to paleontology, dating back to the Triassic Period. It was found in what is now Argentina in 1958. Despite its apex status during its heyday, the Herrerasaurus is relatively small when compared to later predators, only reaching slightly more than a meter and half in height. The exact classification of this dinosaurs is heavily debated. Some paleontologists have classified Herrerasaurus as a basal saurischian, while others have theorized this carnivore may actually be a prosauropod. Some have even placed it outside of dinosauria entirely. Jurassic Park’s brilliant InGen scientists determined that Herrerasaurus was a basal theropod.

The Herrerasaurus paddock wasn't yet open for visitors during the 1993 incident. The paddock is believed to be located near the tour gates, being amongst the last species on the Jurassic Park tour. When the park was sabotaged, 3 to 4 juvenile Herrerasaurus specimens escaped from their enclosures. While reports are dubious, it is alleged that they reached the rumored under-construction attraction called the Bone-Shaker. The animals proved to be agile and efficient jumpers while attacking survivors. It is said that Herrerasaurus devour large chunks of prey whole, and are capable of digesting bone.

The Herrerasaurus cloned by InGen sport a rather colorful and exotic pattern. Their skin is predominately a deep red with a white belly. Their vivid yellow backs create a sunset gradient broken up by dark rusted brown splotches and stripes. Their eyes are a bright yellow with tiny round piercing pupils while their mouth and tongue are blue in tone.