Hesperonychus (Greek for "western claw"); pronounced HESS-peh-RON-ih-cuss
Woodlands of North America
Late Cretaceous (75 million years ago)
Size and Weight:
About 2 feet long and 3-5 pounds
Small size; long tail; feathers
As so often happens in the dinosaur world, the incomplete fossil of Hesperonychus was unearthed (in Canada's Dinosaur Provincial Park) a full two decades before paleontologists got around to examining it. It turns out that this small, feathered theropod was one of the smallest dinosaurs ever to live in North America, with a weight of about five pounds, dripping wet. Like its close relative, the Asian Microraptor, Hesperonychus probably lived high up in trees, and glided from branch to branch on its feathered wings to avoid larger, ground-living predators.