COLORATION 91 



but from behind there is no countershading effect whatever, 

 the part of the back which is pressed against the ground 

 being as dark as the rest. If natural selection had de- 

 veloped countershading as of survival value on the rabbit's 

 fore quarters, where it can be of use only when the rabbit 

 sits partially raised on its forelegs, it would certainly have 

 developed it for the back and hind quarters, where it would 

 be of use both when the rabbit crouches flat and when it 

 sits with its fore quarters raised. But, as a matter of fact, 

 the countershading probably has no effect — certainly no 

 appreciable or survival effect — in concealing the rabbit, 

 which is just as difficult to make out when seen from the 

 rear as when seen from the side. Rabbits, like mice, 

 gophers, and the immense majority of small mammals are 

 hard to make out merely because their general tint is incon- 

 spicuous, wholly without regard to the countershading or 

 the details of the pattern, so that the animal escapes detec- 

 tion because it is colored so that it does not strike the eye, 

 and sits motionless like a clod or stump, amid such sur- 

 roundings that the eye overlooks it because of the great 

 abundance of the inanimate objects round about. Cover 

 and immobility primarily, and secondarily a dull color, with- 

 out regard to minute pattern or countershading, are the 

 factors in the animal's concealment. On a perfectly bare, 

 flat, unbroken plain a rabbit or a gopher is seen at once, at 

 a long distance; even a mouse is visible under such condi- 

 tions, and, therefore, meadow mice are most reluctant to 

 venture beyond the protection of the grass, under the cover 

 of which they pass their lives. 



The zebra has an unholy fascination for the entire school 

 of ultra selectionists, ultra concealing-colorationists — prob- 



