In an undated photo provided by the Cranbrook Institute of Science, Eric Stamatin, left, and Andrew Gainariu stand outside the museum in Bloomfield Hills, Mich. Stamatin, 11, of Shelby Township, and his cousin, Andrew Gainariu, also 11, of Troy, found the mastodon bone over the summer while exploring in Eric's backyard near a stream in the 24 Mile and Dequindre area. "At first it just looked like a rock, but it had a hole in it so we thought maybe it was a bone," Eric said. A research scientist with the Institute confirmed the fossil the boys stumbled across was an axis bone of the extinct American mastodon. (AP Photo/Cranbook Institute of Science, HONS)