Instinctive behaviors of the domestic dog are comparable to those of its wild relatives, the wolf, coyote, fox, and jackal. Unlike trained behaviors, such as being housebroken or responding to human commands, instinctive behaviors are those that dogs do without being taught and include vocalizations, body language, and marking. For example, by four weeks of age, puppies bark, whine, growl, and howl—-just like their wild relatives. Even the African Basenji, known as the barkless dog, yodels when aroused. These sounds, whether elicited in excitement, fear, territoriality, or pain, are one way that dogs communicate with one another and with other animals and people.
Dogs also communicate through their use of body language. Facial expression, ear posture, tail carriage, hackle (hair on back) display, and body stance signal a dog’s state of fear, excitement, aggression, or submission. Understanding the meaning behind these signals can be important. Signs of potential hostility in a dog include bared teeth, flattened ears, erect tail, stiff legs, and bristling back hair; the dog may also growl or bark. People observing these behaviors should keep their arms at their sides and slowly back away, while firmly saying “no.” When approaching a strange dog, first ask the owner if the dog may be touched. Once given permission, hold the hands low and speak softly. Staring directly at a dog may arouse intimidation or aggression, so eye contact with strange dogs should be avoided.
Dogs typically mark their territory with urine as part of the social communication between animals in general and among the species. A dog may defend the territory by growling, barking, or assuming aggressive body language.
In addition to these instinctive behaviors, dogs are capable of learning certain trained behaviors, such as following obedience commands. The domesticated dog is able and willing to learn appropriate behaviors and is highly motivated to please its owner, critical factors that have contributed to the success of the domestic dog as a companion.