COLORATION 141 



Five years later (October 15, 1904), my sister, Mrs. Florence 

 Merriam Bailey, and I, accompanied by Henry Gannett, of the 

 Geological Survey, spent a night in the Grand Canyon, near the 

 Cameron Trail. We had no water, and no food except some 

 canned corned beef, which made us so thirsty that we ate very 

 little. At dusk a family of little spotted skunks appeared. They 

 showed little fear of us, and none at all of the small fire we had 

 kindled. I tried the experiment of tossing them pieces of the 

 corned beef, which they seized greedily. They were on grayish 

 rocks, against which background their black bodies were easily 

 seen; their white markings also were rather conspicuous. 



While shuffling about, searching for morsels of the corned 

 beef, they showed no fear so long as we stood still, but if we took 

 a quick step or made any sudden move they instantly vanished. 

 At first I thought they had gone in among the rocks, but soon saw 

 that they had not moved away. This struck me as so extraor- 

 dinary that I tried the experiment of frightening them. This I 

 repeated a number of times, and each time the animal or animals 

 nearest my feet immediately became invisible. All traces of 

 black and white had disappeared, and even the outline of the ani- 

 mal could not be made out against the uniform grayish back- 

 ground of rocks and sand. The sudden transformation was most 

 puzzling. The moon was full, but my notes are not clear as to 

 whether it had risen high enough to shine down into the part of 

 the canyon where we were; probably it had not. At all events, I 

 was utterly unable to see the spilogales in the act of changing 

 color, and could not be positive as to how they did it. I was 

 convinced, however, that the change from conspicuousness to in- 

 visibility was brought about, under the influence of excitement 

 or fear, by the erection of the body hairs in such manner that the 

 white and black markings blended to form a neutral, grayish drab, 

 rendering the animal completely invisible. The deception was 

 doubtless heightened by the solid black of the top of the head 

 and basal half of the tail, for at night black areas pass for shadows 

 or hollows — thus tending to mask the body form by cutting out 

 the dark parts. 



In most kinds of open country, as every field naturalist knows, 

 grays and drabs are "obliterative" both by day and by night. 



