Police dogs are great for the kids and the press. They're adorable and obedient. But when they are working, they are quite a different sight.
This is one of those situations where TV captures reality pretty well. Giant dogs prepared to take people down with subtle cues from their handlers is precisely what happens when it is time for a police dog to go into action.
We've come to trust these dogs implicitly, but what happens when they're wrong? Or when they use too much force?
Just following orders
By nature, dog's follow orders, not just because we've trained them to, but because, in the domestication process, they have developed a desire to please us. When your dog seems to love all of your friends except for the one who you have a "bad feeling" about, it's not because he has incredible dog intuition. It's because your dog has come to understand your subtle body language and is responding accordingly.
This is the case with police dogs as well. If a handler is suspicious of someone, even with no evidence, a police dog will read those cues and give his handler a coordinating response; even if there is nothing to base it on.
The nose knows what the handler's hands say
What about the dogs that sniff out drugs and bombs? A lot of time and money goes into training dogs to be able to find things that people hide. Dogs are still far better at smelling something than a human, but in the process of learning how to sniff out bombs or drugs, dogs also learn to watch their handlers for cues that there might be something when there isn't.
This doesn't mean that dogs aren't able to smell where a bomb or drug stash might be lurking. It simply means that if the dog's handler has an idea of where it might be, the dog is more likely to pick up on that cue and give a false signal.
This dog's bite is worse than his bark
Often, police dogs are trained to be able to bite and hold a suspect until an officer can make it to the scene. For this to be an effective method of detainment, the bite has to be pretty significant. This often results in puncture wounds on the suspect.
The problem comes in when the dog gets the wrong person or when the dog does more damage than he was trained to do. The latter was the case when one man tried to flee from a traffic violation and a police dog bit and severed his femoral artery.
Of course, police dogs usually get it right, which is why police are still using them. But, like their human handlers, there are certainly cases where police dogs have gotten it very wrong.