Nothronychus was an average sized therizinosaur. It was roughly 16-20 feet long and weighed about 1,000-1,500 pounds. The long claws on it's hand may have been used for defense, food gathering, or display. Therizinosaurs were rare in North America and Nothronychus would have been an uncommon sight. This herbivore lived about 90 million years ago.