so why the dog? >> well done, well done. >> reporter: more importantly, why give the dog a medal? well, here then the beginning. dozer the goldendoodle in 2008. when his new human went to take him home -- that would have been roseanna there with the stick -- all his puppy brothers and sisters had already left. >> he was the dog nobody wanted. >> reporter: which made dozer kind of an underdog. but thenfast forward three years. the sunday morning of the maryland half marathon. 2,000 runners, 13-plus miles, pounding down the road for cancer research. when they passed dozer's house he somehowlipped past the virtual fence meant to keep him inside and joined the runners. caught up in the current there he was. still later, there. out of place but keeping up, without gatorade or power bars. as people snapped his picture all along the route. up ahead, this was it. and somebody actually videotaped