Deinonychus horridus
- "terrible claw"
- Mid-Cretaceous
- 12 feet long

[I didn't get a picture of the plaque, so I'm taking info from one of my books and my own knowledge.]

Known from more than nine skeletons, this is the dinosaur over which the debate about whether dinosaurs were warm-blooded or cold-blooded began. One remarkable deposit has several Deinonychus skeletons scattered around the remains of an ornithopod, Tenontosaurus, (a dinosaur about four times Deinonychus' size) indicating that it was an intelligent pack hunter, likely hunting in small packs of four to six. It was the prototype for the "raptors" in Jurassic Park, although modern renditions often have them covered in feathers. [Of which I am not fond.]

This medium-sized member of the theropods has a killer claw on the hind foot. This claw was large, up to five inches long and had a sharply curved "sickle" shape. Because of this design, Deinonychus probably walked on its third and fourth toes. The second toe (carrying the large claw), designed for extreme retraction was carried off the ground and used in attacking prey, rather than walking. Its light, bird-like body is balanced by a stiff, straight tail. The tail was held straight and each vertebra had bony tendons growing from it that clasped several of the vertebrae behind, solidifying the whole structure into an inflexible pole with only the first six tail vertebrae able to bend and move. The tail was likely used as a rudder and to keep the animal balanced while it slashed away with the killer claw on the second toe. The long, heavily clawed hands are angled so that the palms face inwards, enabling it to clutch firmly at its prey, and had a remarkable degree of mobility, and could flex and turn much like ours.

From the Dinosaur Walk Museum in Pigeon Forge, Tennessee.

~ harui