EXPERIMENTS ON THE RABBIT 157 



This mutual washing seemed their most marked reaction to 

 each other. Corresponding to their lack of social behavior 

 with their own kind was the absence of any , such recog- 

 nition of human beings as a dog or cat would show. Although 

 they were kindly treated and petted, they never seemed to 

 notice us in any way, except that they invariably ran away 

 when approached : no experience could overcome the instinct 

 for flight, probably the strongest instinct a rabbit has. Very 

 likely their lack of eye movements and the fact that, as we shall 

 see, they probably use monocular more than binocular vision, 

 contributed to produce this effect of ignoring us, since it is diffi- 

 cult to judge from its apparent gaze where a rabbit's attention is 

 directed. We never got them to respond in any way to the 

 sound of our voices. They would start at a loud noise, but 

 ordinary noises left them quite unaffected , probably from a pro- 

 tective instinct. 



Gnawing, digging in the dirt, running, leaping with all four feet 

 in the air, seemed to be their chief activiites. When pursued 

 they almost never ran in a straight line, but displayed the use- 

 ful instinct of doubling. One instance of an individually acquired 

 habit is interesting. In the small room where the experiments 

 were carried on after cold weather set in there was a box contain- 

 ing earth. Dark Nose happened to jump in this box one day 

 when we were trying to catch her, and allowed herself to be 

 picked up from it and dropped before the experiment box. 

 From that time on, with occasional exceptions, she made a prac- 

 tice of jumping into the earth box between experiments and 

 waiting to be picked up from it and dropped in front of the 

 experiment box. As soon as she had opened the correct door and 

 got food, the experiment box would be removed, whereupon she 

 would immediately run to the dirt box, jump in, and wait, often 

 for several minutes, until the experiment box was ready for the 

 next test, when she would allow herself to be picked up and 

 put before it. Another box containing earth stood in the large 

 laboratory room. When all the rabbits had been tested it was our 

 custom to catch them and put them into the hutch on the roof 

 to spend the night. After the female had formed the habit of 

 jumping into the earth box in the experiment room, she would 

 ordinarily submit to being caught in the large room only when 

 she had jumped into the earth box there. 



