TERRIBLE CLAW

The image below is a photo of the exhibit panel. Following it is a transcript of the panel.

Photo of the panel from the exhibit.

A huge claw on each hind foot armed fast-running Deinonychus for slashing prey.

Deinonychus and its relatives were among the most effective predatory dinosaurs. Slashing claws with special grooves (blood troughs) quickly subdued prey.

Its hands, like the feet of hawks and owls, seized prey. To grab its victim, Deinonychus used a motion that is almost the same as a bird's flight stroke.

Deinonychus (dye- NON -ih-kus): an extinct therapod dinosaur closely related to birds

New features:

  • large, sickle-shaped claw on second toe, used for slashing prey
  • long, overlapping tail bones stiffened and stabilized a shortened tail for better balance

When? 110 to 100 million years ago

Deinonychus Hunting Behavior

    The Hunt Deinonychus hunted in packs. Four Deinonychus skeletons were found with that of a Tenontosaurus victim.

    The Attack To seize prey, Deinonychus swung its long hands and arms out and forward, a motion almost identical to the flight stroke used by birds. Deinonychus couldn't fly, but its arms and shoulder girdle are very similar to those of Archaeopteryx , the earliest bird; the only difference in in length.

    The Kill To subdue its prey, Deinonychus stood on one leg, balanced by its still tail. It moved the second claw on its hind foot in a wide arc to slash, stab, and disembowel its victim.

See what fossil evidence tells us about how these dinosaurs lived (Out of the Woods).

PICTURE CAPTIONS:

    Diagram showing common ancestry and evolution of Tyrannosaurus , Deinonychus , and birds from organisms with a stiff tail and three functional fingers in hand. Evolution of Deinonychus and birds is where wishbones and "flight stroke" used to seize prey branch off.