CBS’s “Greatest American Dog” has viewers wagging their tails, USAToday says. The reality show’s premiere last week drew an impressive 9.5 million viewers, the paper says, citing figures from Nielsen. The owners and their dogs have already generated fan Web sites. Unlike many human reality show participants, CBS’s dogs are not high-strung, easily flustered or likely to react unhappily to pressures of a new environment and ever-changing demands. There were no mutt meltdowns during filming, but there’s never absolute predictability with animals, so “there are lots of surprises,” R.J. Cutler, the show’s executive producer tells the paper.