Deinonychus: Cretaceous Predator

Deinonychus was an agile, lightly-built therapod that lived during the Cretaceous Period in North America. The velociraptors in the film Jurassic Park actually resembled deinonychus more than velociraptor, which in reality only reached about three feet in height. Fossils of deinonychus have been unearthed in Montana, Utah, and Wyoming.

Deinonychus can be considered the wolf of the Cretaceous, with its keen predatory features and its relatively large brain. It was around ten feet long and five feet tall, weighing only 175 pounds. Its long, powerful hind legs and low body weight would have allowed it to run at a pace faster than most herbivores. Its speed would have aided it as an ambush predator, allowing deinonychus to attack quickly with the element of surprise. Its long, rigid tail provided the balance needed for agile and explosive movements. Although deinonychus had the potential for quick bursts of speed, it is unlikely that it was able to reach speeds it attains in the popular eye. The length of its legs is shorter than that of comparatively swift dinosaurs around the same size like struthiomimus, so going on this data alone it would have meant that deinonychus was certainly slower than modern flightless birds. However, recent studies into the possible musculature of deinonychus legs reveal that it might have possessed different muscles used in operating its claw and running. So the speed of the animal is still open to debate among scientists. Its light build with long legs and a large narrow skull made deinonychus very birdlike, and it is suggested that birds evolved from smaller versions of carnivores like deinonychus during the Cretaceous Period.

This small carnivore had large eye sockets in its skull, which suggests that it had keen binocular vision enabling it to zero in on prey more easily. It had three long, clawed fingers on its forelimbs which would have enabled it to slash and grasp at prey. This is unlike many of the larger therapods like Tyrannosaurus which had puny two-fingered limbs which would have been useless in helping to subdue prey or keep balance. Perhaps the most striking feature of deinonychus is the sickle-like claw present on the second toe of each foot. This claw was retractable which would allow the dinosaur to run effectively, but could be brought forth to deliver devastating stabs to prey items. It was once thought that the dinosaur used this claw to slash and disembowel prey, but this has recently been cast into doubt due to the leg mechanics and balance needed to perform such an action.

It has been suggested that deinonychus hunted in packs like modern-day wolves in order to bring down large prey more effectively. This is a possibility given deinonychus' body and brain size, although it would have been equally effective at chasing down small prey like early mammals or other small dinosaurs. Furthermore, several skeletons of deinonychus have been preserved in a single find alongside a large herbivore, tenontosaurus. In any case, deinonychus was a killer, and a very smart killer by dinosaur standards. Its brain-to-body ratio was very large, even compared to other therapods, which were among the smartest of the dinosaurs. The same trend can be seen today, where predators are comparatively smarter than their herbivore contemporaries. Carnivores need to outsmart their prey in order to catch it. Herbivores only need to know how to run, swing a tail, or defend in numbers.

Deinonychus became extinct at the end of the Cretaceous Period, when all dinosaurs were wiped out in the devastating Cretaceous-Tertiary mass extinction.