Body Language

• The most important tool dogs use to alert handlers is body language. Canines speak their feelings through their posture, face and tail. A wagging tail, slightly open mouth (but not baring teeth) and relaxed overall posture signal that the dog is having fun. Rolling the ears back, tense overall posture and bared teeth signal the dog is experiencing stress. The dog may react with either fear or aggression in a given situation, but both of these reactions can create situations which spiral out of control for the handler.
  
  

Vocalizations

• Vocalizations are the complement to the dogs' body language. Dogs instinctively whimper as puppies to get their mother's attention. After they leave their mother, they see that whimpering does not yield the same results as before and so they turn to barking, howling, and growling to get attention. Each of these can alert a handler to a different need. Whimpering or crying may mean that the dog has a need (warmth, sleep or food.) Barking can be a cry for attention or a warning about an upcoming stressful situation. Growling usually alerts the handler to reaction to a stressful situation.
  
  

Submissive Urination

• Submissive urination happens when a particularly submissive dog is overexcited by any environmental stressor. These include over-excited greetings, strangers in the home and loud noises such as thunder. Many handlers consider submissive urination a minor annoyance, but it's an important communication tool for dogs to express their stress. If a dog urinates every time a certain event occurs, the dog is likely trying to alert the handler to the stressor.
  
  

Sensory Cues

• Canines have a stronger sense of smell and hearing than their human counterparts. Dogs may alert their handlers to certain threats or items of interest in a given environment by giving sensory cues. For example, a dog who cocks its head and ear has just noticed a new sound, and the handler should be on alert for what this new sound might mean. The same goes for a dog who is sniffing a particular area. Additionally, canines can be trained to react to certain scents like drugs and explosives with a vocalization to alert a handler to their presence.