Open main menu

Page:Popular Science Monthly Volume 44.djvu/612

This page has been validated.

difficult, not to mention that the noise would cause them to flee. The Toxotes knows a better trick than that. He draws in some drops of water, and, contracting his mouth, projects them with so much force and certainty that they rarely fail to reach the chosen aim, and to bring into the water all the insects he desires (Fig. 2). Other animals also squirt various liquids, sometimes in PSM V44 D612 The toxotes throwing water at insects.jpgFig. 2.—The Toxotes throwing Water at Insects. attack, but more especially in defense. The cephalopods, for example, emit their ink, which darkens the water and allows them to flee. Certain insects exude bitter or fetid liquids; but in all these cases, and in others that are similar, the animal finds in his own organism a secretion which happens to be more or less useful to his conservation. The method of the Toxotes is different. It is a foreign body which he takes up, and it is an intended victim at which he takes aim and which he strikes; his movements are admirably coordinated to obtain a precise effect.

Another fish, the Chelinous of Java, also acts in this manner. He generally lives in estuaries. It is therefore a brackish water which he takes up and projects by closing his gills and contracting his mouth; he can thus strike a fly at a distance of several feet. Usually he aims sufficiently well to strike it at the first blow, but sometimes he fails. Then he begins again until he has succeeded, which shows that his movements are not those of a machine.

Methods of Utilizing the Captured Game.—Frequently it is not enough for the animal to obtain possession of his prey. Before making his meal it is still necessary to find a method of making use of it, either because the eatable parts are buried in a thick shell which he is unable to break, or because he has captured a creature which rolls itself into a ball and bristles its plumes.