THE FRESH WATERS 161 



PARENTAL CARE AMONG FRESH- WATER 

 ANIMALS 



The common little Bullhead, or Miller's 

 Thumb, has also to take precautions against 

 having its eggs washed away or damaged by 

 running water. This little fish is regarded 

 with some awe by country children, because it 

 apparently utters a cry when it is caught and 

 taken out of the water. But the "cry" is no 

 more produced by vocal organs than is the 

 buzzing of the bee, or the chirping of the grass- 

 hopper. The bullhead, in common with a 

 good many other fishes, has the habit of 

 supplementing its gill-breathing by coming to 

 the surface and swallowing a mouthful of air, 

 and it is the sudden rush of this air out of its 

 body that causes the sound. The bullhead 

 lives a solitary life, usually hidden among the 

 stones at the bottom of a rapid stream. It 

 scoops out a nest beneath a stone, to the under- 

 side of which it fastens its cluster of eggs. 

 Unlike the lampreys, which show no care for 

 their eggs after they have been deposited, the 

 male bullhead remains on guard over the eggs 

 and young fry for about a month. Then the 

 family breaks up, and the young ones seek out 



ii 



