830 THE POPULAR SCIENCE MONTHLY. 



cock-fighting, and often stake large sums, or even the freedom of them- 

 selves 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 wnth their pugnacious rivals. It is then 

 especially that their bodies assume the beautiful transparent and irides- 

 cent 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 con- 

 tests, 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 shoAvn, the most beau- 

 tiful animal is also the strongest and most efficient, and the periods of 

 high vitality are always accompanied by the most ornamental devel- 

 opments and the most vivid coloring. From generation to generation, 

 the strongest, best armed, and most brilliant sticklebacks have con- 

 quered the feebler or uglier in battle, and have been selected as hus- 

 bands 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 origi- 

 nally 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 con- 

 trary, 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. 



