The male salmon is as pugnacious as the little stickleback. Two males have been known to virtually battle with each other all day long. In breeding ponds the males can be seen constantly fighting and tearing one another on the spawning beds, and so many are injured in consequence that they may be seen swimming near the banks in a state of exhaustion, many of them apparently dying. Among birds the law of battle holds as well as the law of preferential mating. During the breeding season they are exceedingly pugnacious. The humming birds, the smallest of any, are among the most quarrelsome. Two males rarely meet without a fierce fight on the wing. Darwin gives the following illustration of the invincible courage and fighting instinct of the gamecock. One of these birds had both of its legs broken in a cockpit, and its owner made a wager that if his legs could be supported with splints and bandages so that he could stand upright he would keep on fighting. This was accomplished, and the bird fought on with dauntless courage until he received a death stroke. It is probable that even with the most pugnacious species of birds the pairing does not depend alone on the courage and strength of the male, for these males are usually decorated with various ornaments. Furthermore, these decorations during the breeding season often become more brilliant, and are eagerly displayed before the females. Darwin states that twenty or more males of the _Tetrao cupido_ (species of grouse) will assemble at a particular spot, keeping up a tremendous chattering and strutting about. At the first response from a female the males take to fighting furiously, and the weaker are vanquished. Both the victors and the vanquished pay court to the female, so that the latter must make a choice or the battle is renewed. Here we have the combined action of selection through battle and by preferential mating. Among mammals the males win the females much more through fighting than through the display of charms. In the breeding season the most timid male animals, which are not even supplied with any special weapons for fighting, engage in the most desperate conflicts. Two male hares have been seen to fight until one was killed. Those male mammals which are provided with special weapons for fighting enter into the fiercest and most deadly conflicts. The wild male elephant, during the period of love, is one of the fiercest fighters in the world. Lions engage in terrible battles, and a young lion dare not approach an old one. Male seals fight most desperately during the breeding season, using both their claws and teeth. The conquerors appropriate the females and transmit their qualities to their offspring. These are all cases of the survival of the fittest; of the survival of the males best adapted to the exigencies of their surroundings—in short, additional illustrations of Natural Selection.