Page:Popular Science Monthly Volume 32.djvu/799

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MONG the nest-building fishes which inhabit German waters, the most interesting is the tiny "stickleback," whose life-history has been carefully studied. The home of this little animal is some-times found in ditches, hanging among branches and twigs of plants; the nest is about the size of the average hand, and in structure and material bears a marked resemblance to the round nest of the tit-mouse. It is a peculiar and remarkable fact that among the sticklebacks the hatching is done by the male and not by the female fish. The building of the nest, a task to which the male also attends, is an interesting event. For many days in succession the little animal, whose energy and perseverance are truly worthy of admiration, collects its material, which consists of loose stalks, plant-shreds, root-fibers, and grass. These it assorts carefully, discarding all material that proves too light. It often drags along pieces exceeding its body in length, and sometimes with great exertion strips growing plants. All this material is worked up into a tangled mass, and layers of sand are scattered in between. The nest is rendered firm by a glue-like juice, which the little mason excretes after the completion of each layer, gliding slowly over the structure; this causes the separate parts of the nest to adhere closely together. The whole, when completed, has the appearance of a sand-hill, and is detected with much difficulty. While at work the fish rarely partakes of any food; it seems that during this blissful period of its existence it finds no pleasure in such everyday events; but with intense animosity it drives back any jealous rivals, larvae, salamanders, or water-bugs, which cross its path, sometimes with evil sometimes with harmless intentions. After the troublesome hatching-time is over, the anxious papa still continues to care for his numerous offspring; by day and by night he watches over them, and drives away all creatures whose approach seems dangerous. This unremitting watchfulness ceases only when his young are able to raise their weapons of defense and have become somewhat acquainted with their surroundings. Any inquisitive little one venturing too far away is quickly sent home, and it actually happens that those who are very disobedient are imprisoned in the nest. The home-life of these little animals really presents an abundance of interesting and touching traits.

To study the family of fishes which inhabit the ocean and sea-gulfs is naturally more difficult, and rarely proves as successful as observation extended to the inhabitants of our fresh-water lakes, rivers, and streams; but, by the co-operation of naturalists, fishermen, and sailors, many events happening in the deep seas have been observed that afford