Researchers discover trails of a mysterious, two-legged swimming dinosaur with bird-like characteristics in northern Wyoming.

They are now searching for bones and other remains to identify and name the primitive creature.

Debra Mickelson, a University of Colorado graduate student in geological sciences says, "It was about the size of an ostrich, and it was a meat-eater. The tracks suggest it waded along the shoreline and swam offshore, perhaps to feed on fish or carrion."

Mickelson says the tracks indicate a 6-foot-tall dinosaur lived approximately 165-million years before. He says, "The swimming dinosaur had four limbs and it walked on its hind legs, which each had three toes. The tracks show how it became more buoyant as it waded into deeper water - the full footprints gradually become half-footprints and then only claw marks."