164 American Fisheries Society 



When the red hard-heads thus equipped with stinging 

 tentacles were thrown to the snappers they at first ate 

 them. But a single experience was enough to teach the 

 average gray-snapper that the tentacled hard-heads were 

 not good to eat. After taking one he did not care for 

 more. Not only did the grey snappers stop eating these 

 red fish — but during the rest of my stay on the islands 

 they would not touch them. Nearly three weeks after 

 their first experience they still refused red hard-heads 

 even when they were not equipped with tentacles. At 

 the same time they ate hard-heads of other colors. Thus 

 the snapper not only learned to let red hard-heads alone, 

 but they learned also to tell them from those of other 

 colors. That fish in general may learn to avoid a lure 

 or baited hook seems clear. Whether they do avoid it 

 depends in any particular case on how hungry they are, 

 for a hungry fish, like a starving man, will eat almost 

 anything. 



Many years ago Moebius (1873), placed a pike in an 

 aquarium which was divided by a partition of glass. 

 On the opposite side of the partition from the pike he 

 placed some minnows. The pike made frantic efforts 

 to get the minnows, but at each attempt, bumped his 

 snout against the glass. After a time, profiting by ex- 

 perience, he ceased to try. The partition was then re- 

 moved so that the pike had free access to the minnows. 

 But he had learned his lesson, and did not try to get 

 them. Thus a happy family was created ; the lamb and 

 the lion lay down together. But finally the pike, perhaps 

 because he grew hungry or because he happened to bump 

 against one of the minnows, made another attempt and 

 succeeded. The minnows then disappeared very quickly, 

 for the pike had learned once more. The experiments 

 of Moebius were repeated by Triplett (1901), who used 

 perch instead of pike and obtained results like those of 

 Moebius. 



More recently Thorndike (1911), and Goldsmith 

 (1914) , have shown that fish may learn to come to a par- 

 ticular point in an aquarium to be fed and that they re- 



