** FILE ** Cowboy, a black-and-white Border Collie searches for victims in the rubble of the New York's World Trade Center for the Federal Emergency Management Agency, in this Sept. 21, 2001 file photo. Scientists have spent years studying the health of search and rescue dogs that nosed through the debris at ground zero, and to their surprise, they have found no sign of major illness in the animals. (AP Photo/Alan Diaz, File)