The primary object of a hostile meeting between dogs (as well as between higher animals) is to decide a question of precedence, either general or particular. Now, if we could only settle which was the best man in any dispute by duels à outrance, a great deal of blood would be shed unnecessarily, and many valuable lives lost to the community. The introduction of moral weapons is therefore a great point gained, for injury to one is injury to all. The quick recognition of the superiority of a foe, and the perception of when submission should take the place of valor, is plainly of advantage to the individual, since a pig-headed obstinacy in resistance would frequently lead to elimination. Where in the serious business of life there is an interdependence of individuals associated for common ends, any influence which lessens the severity of internecine conflicts tends to the general well-being. Just as commanding officers have forbidden duels between members of an army in the field, so Nature has among gregarious animals, and especially those of predatory habits, discountenanced strife which might weaken the general efficiency of the pack.
Few animals excel the dog in the power of expressing emotion. This power is a sure sign of an animal which is habitually in communication with its fellows for certain common ends. Although probably long association with and selection by man have accentuated this faculty, a considerable share of it was undoubtedly there from the beginning, and was of service long before the first dog was domesticated. It is easy to see how important it is for the general good that the emotions of any one member of a pack of dogs should be known to the others. If, for instance, one of the number should perceive an enemy, such as a snake or leopard, lying in ambush, his rapid retreat with depressed tail would instantly warn the others of the danger.
There are many reasons for the tail being the chief organ of expression among dogs. They have but little facial expression beyond the lifting of the lip to show the teeth and the dilatation of the pupil of the eye when angry. The jaws and contiguous parts are too much specialized for the serious business of seizing prey to be fitted for such purposes, as they are in man. With dogs which hunt by scent the head is necessarily carried low, and is therefore not plainly visible except to those close by. But in the case of all hunting dogs, such as fox-hounds, or wolves which pack together, the tail is carried aloft, and is very free in movement. It is also frequently rendered more conspicuous by the tip being white, and this is almost invariably the case when the hounds are of mixed color. When ranging the long grass of the prairie or jungle, the raised tips of the tails would often be all that an individual member of the band would see of his fellows. There is no doubt that hounds habitually watch the tails of those in front