230 Studies in Animal Behavior 



cates that they are drawn toward the females by the 

 sense of smell. Mating apparently is dependent 

 upon the chance meetings of the sexes. "During the 

 mating season," says Pearse, "the instinct of the 

 male is to grasp and turn over every crayfish that 

 comes in his way. ... If this individual is a female 

 of the same species the attempt may meet with suc- 

 cess, but if it is a male or a female of another species 

 the effort at sexual union is usually of short dura- 

 tion." If males attempt to mate with other males, 

 as they often do, they encounter active resistance, 

 but if a female is attacked she usually remains pas- 

 sive. 



In fishes the males are frequently distinguished by 

 their more conspicuous coloration especially during 

 the breeding season. The pugnacity and threaten- 

 ing attitudes of the males at this time undoubtedly 

 contribute to their mutual recognition, but there is 

 evidence that the mature males often recognize one 

 another by their peculiar markings. In her account 

 of the breeding habits of the rainbow darter, Miss 

 Reeves records several cases of young dull-colored 

 males being mistaken for females, whereas the larger 

 and more brilliantly colored adults usually recognize 

 one another without difficulty. "The more nearly 

 the behavior of a dull male simulates that of a 

 female, as in the case of a male burrowing for food, 

 the more is he likely to be taken for a female. Upon 

 the near approach of the brilliant male the young 

 male erects the first dorsal and rapidly escapes, 



