Play and Aggression
Most dogs are extremely playful, even once they have grown up. A dog uses a classic pose often called the “play bow” to start play. The head and front quarters drop to the ground, the hind legs remain upright with the hindquarters in the air, and the tail is held high. This indicates that what follows will be play.
It is important for one dog to communicate this to another because during play the normal relationships between dominant and submissive individuals will be temporarily abandoned. A dominant animal may sometimes fall on its side in a submissive gesture to a smaller dog in order to encourage play.
Play is first seen in young puppies aged about a month, when play fights act as a rehearsal for adult behavior, building muscles and improving coordination and reaction times, which would all have been essential when the dog’s ancestors had to hunt in order to survive. It is not know exactly why adults continue to play. In the domestic dog, playfulness was probably encouraged by human companions during the period of domestication, but even in the wild some animal still occasionally indulge in play.
Some dogs are often described as aggressive, but aggression is not a single type of behavior. There are probably about eight varieties of aggression that may be exhibited by dogs, and all have different causes that can be isolated.
Predatory aggression or the catching of prey is seen when a dog chases a bird, or a rabbit or even a cat. This type of aggression is never normally directed at humans. If a dog is thought to attack a person as police dogs are this is an example of trained aggression and will not occur without a spoken command. Territorial aggression in humans, usually in the form of a threatening posture. A dog may defend its territory against its own species as well as against people. This behavior is usually seen in dominant dogs, or if the owner is absent for a period, when the dog may assume territorial dominance. Postmen may especially notice this, if they wear a distinctive uniform, and retreat. The dog will be encouraged to threaten again next time in defense of its own territory. Male dogs tend to be more aggressive than females. Fear-induced aggression probably accounts for many of the dog bites that are suffered by children. Dogs who are not used to children may be frightened by a child rushing up with outstretched hands. What is intended as a friendly gesture can easily be interpreted otherwise by the dog. Keeping an eye on children, if there is an unfamiliar dig about is a sensible precaution.
Pain induced aggression is similar, except that the dog reacts to a genuinely painful stimulus. Dogs that have been injured may therefor snap unexpectedly and should be handled gently – or muzzled if necessary.
Some dogs are especially prone to getting into fights with males. This appears to have something to do with male sex hormones. A mother protecting her puppies may also at times be aggressive. This is comparable if only because she is in a special hormonal state at this time.
The final type of aggression results from competition for something desirable, such as food or even affection from the owner. In the wild most competitive fight would soon be resolved by signals such as threats followed by submission. In the case of pet dogs, however, the protection offered by an owner to an underdog may interfere with the natural resolution of conflicts.