This July 4, celebrate America’s freedom, but don’t forget the brave dogs who help us keep it. More than 100 bomb-sniffing bowsers hit the streets of New York every day at such high-profile targets as the Staten Island Ferry terminal, the 9/11 museum, government complexes, the Empire State Building and sporting events, with superagent noses that can can detect explosives down to a few parts per billion. More.