More than 5 million people ride the subway trains of New York everyday and when you look around, you do not know who is a target or who is a terrorist. That is why the police department employs canine subway police as a part of the NYPD Transit Unit. These dogs can pursue criminals, track down missing persons, locate dead bodies, sniff out explosives chemicals and conduct transit patrols in city subways. One of the standout canine transit patrol officers is Officer Danz, a 6-year-old German Shepherd.

The subway system is a working dog's nightmare. It's loud, hot, and packed with people. There are only a few dogs that can handle this hostile environment. With the moving trains and the constant crowds, only highly trained dogs will make the cut. "It's not meant for all dogs," explains Officer Danz's partner Officer Wayne Rothschild. "There are a lot of different issues down here. You have stairs, you have slippery floors, and you have the loud noise from the train. And just the vast amount of people we encounter daily. It's a challenge for them."

Officer Danz is considered a police dog prodigy. He can filter out the distractions of this extreme environment and makes use of his special skills in one of the busiest subway stations in the world: Times Square. The canine is use to the loud noises but jumps into action when he hears a gunshot. "Most dogs hear the gunshot, they kind of get afraid and go backwards, don't want to go in where he's got to go in and take care of business," explains Officer Danz's partner Officer Wayne Rothschild.

Although Officer Danz can take down a criminal within a matter of moments, there is one enemy that he cannot defeat: the heat. "You only have about 20 to 30 minutes of working especially when the temperatures are over 90 degrees," says Officer Rothschild. Since dogs are not able to sweat, they must pant to try and stay cool. A few degrees more could be deadly. "The signs of him being overly exhausted are his tongue is out, his drool is coming and his drive has decreased. At some point you have to give him a 15 minute break and some water to cool him down." The Transit Unit has designed a mobile air conditioning kennel where the dogs can cool down fast.

According to Police Chief James Meehan of New York's Transit Police, his department would like to expand their present force of 12 dogs to as many as 75 dogs to assist his officers with patrolling the NY subway system. Finding the right dog and training take a long time but it's worth it because of the invaluable efforts of the canine force.

The dogs normally serve about seven years with the Transit Unit. Once they retire, they live at home with their NYPD partner.