In the months of July and August it would be difficult to find a stream, large or small, swift or slow, lake, pool, or muddy estuary, east and west of the Cascade Mountains, that has not in it immense shoals of that most irritable and pugnacious little fish the stickleback, ever ready on the slightest provocation to engage in a battle. Let friend or foe but rub against his royal person, or come nearer his private subaqueous garden than he deems consistent with safety or good behaviour, in a moment the spines are erected like spear-points, the tiny eyes glow with fury, the colours decking his scaly armour intensify, and flash with a kind of phosphorescent brightness, until the diminutive gladiator looks the impersonation of rage and fury; but as we cultivate his acquaintance, and gain a better knowledge of his real character, we shall discover that his quarrelsome disposition is not so much attributable to a morose temper, and a love of fighting for fighting’s sake, as to a higher and more praiseworthy principle. No amount of thinking would lead one to imagine that his pugnacity arises from intense parental affection: a love of offspring, scarcely having a parallel in the living world, prompting him to risk his life, and spend a great deal of his time in constantly-recurring paroxysms of fury and sanguinary conflicts, in which it often happens that one or more of the combatants gets ripped open or mortally stabbed with the formidable spines arming the back. Skill in stickleback battles appears to consist in rapidly diving under an adversary, then as suddenly rising, and driving the spines into his sides and stomach. The little furies swim round and round, their noses tightly jammed together; but the moment one gets his nose the least bit under that of his foe, then he plies his fins with all his might, and forcing himself beneath, does his best to drive in his spear, if the other be not quick enough to dart upwards and escape the thrust; thus squaring they fight round after round until the death or flight of one ends the combat.