Fish That Travel on Land 



When the tide goes out and strands'these fish in a shallow pool.'they leave the water, and 



actually flop over land to the sea. They never get lost and travel in the wrong direction, 



but always take the straightest road back to deep water 



SCIENTISTS rarely go a-fishing in 

 troubled waters ; Professor S. O. 

 Mast, however, of the zoological de- 

 partment of Johns Hopkins, is an ex- 

 ception. The Johns Hopkins professor 

 discovered that such fish as minnows 

 are often found in the little temporary- 

 pools left in the sand by the tide, but 

 rarely, if ever, after the water in such 

 a tide is so low that the outlet is closed. 



When the tide is falling, these fish — 

 fiindidus majolisis, the scientific name 

 for them — swim out, somehow knowing 

 when the tide is about to get so low that 

 they might be trapped in the little 

 pools in the sand. As the tide falls, they 

 swim in and out of such tide-pools at 

 short intervals. Thus, these fish avoid 

 being trapped in the pools and killed 

 when the little collections of water dry 

 during low tide. 



Professor Mast has observed that the 

 outlets of such tiny pools may be closed 

 while the tide rises, but if they should 

 close while the tide is falling, the fish 

 swim about rapidly in various directions 

 to discover water. If they find none, 

 they leave the water and actually flop 

 over land to the sea. Professor Mast 

 has seen scores and scores of these fish 

 leave large pools and travel across sand- 

 bars more than twelve feet wide and 

 half a foot high. The fish nearly always 

 leave the pools on the side towards the 



sea. They evidently remember the di- 

 rection of the outlet and the direction 

 from which they entered. 



Curiously enough, they never make 

 any mistakes in "walking" on dry land, 

 either. Professor Mast never found one 

 to take a wrong direction for any great 

 distance. Although he admits that it is 

 not yet definitely known how fish are 

 guided in the right direction, it is certain 

 that light reflected from the water is not 

 a factor in this sense of direction. 



Perhaps one of the most interesting 

 discoveries made by the Johns Hopkins 

 zoologist shows how fish can make their 

 way on dry land.. 



Of course, locomotion on land by fish 

 can be brought about only by successive 

 leaps and jumps produced by rapid bend- 

 ing and wriggling of the body or side- 

 swiping by the tail. 



When trapped in a pool which rapidly 

 dries up or evaporates, they swim about 

 for a few minutes, then come closely to 

 the edge of the water and swim up and 

 down the side of the pool nearest to the 

 sea. Finally a dense aggregation of fish 

 forms in the outlet near the dam. and 

 three minutes by the w^itch after thev 

 are shut in, they manage to climb out 

 on the sand. They leave in groups of 

 twelve and "march" like General Sher- 

 man to the sea. These fish are superior 

 to some men in finding their way home. 



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