cock-fighting, and often stake large sums, or even the freedom of themselves and their families, on the prowess and skill of a particular betta. The license to exhibit fish-fights is farmed by Government, and brings in a considerable revenue to the King of Siam.
Now, much the same thing happens on a lesser scale during the battles of the sticklebacks with their pugnacious rivals. It is then especially that their bodies assume the beautiful transparent and iridescent colors so poetically described by Mr. Warington. Their vitality rises to its highest point, and their eyes sparkle like a girl's at a ball with the most vivacious brilliancy. But when a hapless stickleback is conquered in the lists, says Mr. Darwin, "his gallant bearing at once forsakes him; his gay colors fade away; and he hides his disgrace among his peaceable companions, but is for some time the constant object of his conqueror's persecution."
It is pretty clear, then, that the stickles and lateral spines of the stickleback have been mainly developed, like the spurs and wing-weapons of birds, the tusks of boars, the antlers of deer, and the horns of lizards, for the purpose of combating rivals in these annual contests, and of securing the favor of the female fish. The same thing is also true of their beautiful colors, or rather, both are but different sides of the same question; for, as Mr. Wallace has shown, the most beautiful animal is also the strongest and most efficient, and the periods of high vitality are always accompanied by the most ornamental developments and the most vivid coloring. From generation to generation, the strongest, best armed, and most brilliant sticklebacks have conquered the feebler or uglier in battle, and have been selected as husbands by the greater number of their fastidious mates. None but the brave deserve the fair; and, among sticklebacks, none but the brave succeed in winning them. I do not doubt that the stickles also prove incidentally useful to the fish in protecting him from the attacks of larger predatory species; sticklebacks are seldom attacked by perch or trout, and an instance is on record where a pike has been choked by one of these tiny creatures, which erected its sharp spines in his throat as the greedy monster tried to swallow it; but this secondary purpose is only a derivative one; the spines themselves must originally have been developed, as in all other cases, for the wedding tournaments between stickleback and stickleback. It is thus that the horns and tusks of higher animals primarily produced in the internecine combats of the males are occasionally employed for external defense; thus that the spurs and beaks of birds are occasionally turned to the protection of their fledglings. But it may be laid down as a general law of biology, in spite of misconceptions and misstatements to the contrary, that no animal habitually and normally fights any other creatures except individuals of its own species. Dog fights dog, and tiger tiger; but game-cocks do not engage with turkeys, nor do stags usually join battle with buffaloes or bears.
