PERSEVERANCE REACTIONS IN PRIMATES AND RODENTS 29 



myself. For several weeks it was my daily practice to remove 

 the little mound of earth with which the animal occluded this 

 burrow mouth and to flood the burrow with water. My per- 

 sistence was equalled by the gopher, who invariably returned to 

 the muddy burrow during the night and concealed its opening 

 with earth. This involved much labor on the gopher's part 

 without advantage, since these animals will not occupy a muddy 

 burrow and will not feed on roots that are growing in well satu- 

 rated ground if roots can be found in moist rather than muddy 

 ground. In this case the gopher's burrows extended to logan- 

 berry roots in desirable feeding ground. 



A much clearer example of gopher persistence in the face 

 of disadvantage was obtained when I put 12 gophers into a 

 large cage in which there were 12 small nests. Each gopher 

 was driven into a nest and I hoped to avoid the slaughter that 

 usually follows any effort to keep a number of these animals in 

 a common cage. It was soon observed, however, that if a gopher, 

 having left his own nest to secure food, invaded another nest 

 after his cheek pockets were filled with grain and bits of carrot, 

 a battle would ensue which would terminate only when one of 

 the combatants was either dead or a helpless cripple. No matter 

 how large and powerful the occupant of the invaded nest might 

 be, nor how small the disputant of his occupancy, the invader 

 did not seem to be deterred by the disadvantageous consequences 

 of his persistence. He would dart into the nest, only to reappear 

 in a moment, thrust out by its rightful occupant, re-enter and 

 suffer a second expulsion, and so on, until exhaustion or death 

 terminated his stupidly persistent repetition of the nest-seeking 

 reaction. A little variation of reaction would have led him to 

 his own nest or, at least, to one less well defended. Within a 

 fortnight all but two of the 12 gophers were slain in this manner. 

 The survivors were two large males who occupied nests at oppo- 

 site ends of the cage. 



During the experiments it was more or less characteristic of 

 all rodent subjects, and particularly so of gophers, that a dis- 

 advantageous experience in a given alley did not seem to deter 

 the animal from reentering it. After a subject had entered a 

 given alley a number of times during the same trial he was apt 

 to become inactive within that alley, so that electrical stimula- 

 tion was necessary to bring about a resumption of activity. 



