May 12, 1921] 



NATURE 



339 



believe that they witness the attempt to carry 

 a theory too far, and a tendency to be blinded, by 

 the dazzling- brilliancy of one set of interpretations, 

 to the value and importance, and even the exist- 

 ence, of others. 



The author's conclusion that all pattern is 

 obliterative does not conflict with the theory of 



Fig. I. — At a distance of seven or eight yards in bright light or at a shorter distance with less illu- 

 mination, the brightly patterned butterfly disappears before the three butterflies of monochrome 

 tint. From " Conceaiing-Coloration in the Animal Kingdom." 



Warning Colours if we bear in mind that oblitera- 

 tion is dependent on distance. This is well 

 shown in Fig. i, where, as the author 

 states, at the right distance or in a sufficiently 

 reduced light, the brightly patterned butterfly dis- 

 appears before the three monochrome ones, even 

 the dimmest. We see here 

 the effacing effect of "con- 

 trasted juxtaposed color- 

 notes," and are led to under- 

 stand the inconspicuousness 

 of the zebra as described 

 long ago by Sir Francis 

 Galton, and to conclude that 

 it is this rather than "back- 

 ground-matching," as main- 

 tained on pp. 135—36, which 

 is the bionomic meaning of 

 its remarkable pattern. But, 

 returning to the butterfly 

 diagrams, it is obvious that 

 anywhere near the striking 

 distance of an enemy the 

 contrasted colour scheme is 

 far more conspicuous than 

 the other three, and this is 

 all that the theory of W^arn- 



ing- Colours requires. That it should be 

 obliterated at a greater distance is all to 

 the good, for, as the present writer has 

 maintained, "all animals with warning colours 

 have enemies, all are liable to special attacks, in 

 times of exceptional hunger, by enemies which 

 would at other times neglect them. . . . Provided 



NO. 2689, VOL. 107] 



such forms are easily seen and avoided by enemies 

 which respect their special modes of defence, it 

 is clearly an advantage to be as far as possible 

 concealed from those which do not respect them " 

 (Trans. Ent. Soc, 1903, p. 573). 



The author's interpretation of the black-and- 

 white pattern of the skunk will be sufficiently 

 clear when F"igs. 2 and 3 are 

 compared, Fig. 2 being the 

 "mouse's or cricket's view" 

 with the sky let down, as it 

 were, into the pattern, and leav- 

 ing a black shape unrecognisable 

 as an animal, while Fig. 3 shows 

 the "sky 'background ' cut off 

 by dark, making his white con- 

 spicuous." To this interpreta- 

 tion it may be objected that it is 

 very doubtful how far a noc- 

 turnal animal like the skunk re- 

 quires to be hidden from its 

 prey, but there is no doubt that 

 it is advantageous for it to be 

 concealed from enemies which 

 mean to attack, and these, so 

 far as I know, are only predace- 

 ous birds which would see it 

 from above against the ground. 

 From these the obliterative effect 

 at a great distance of the 

 skunk's contrasted black and white may well 

 be a protection, but to all large ground 

 animals likely to attack it, it would be extremely 

 conspicuous. Furthermore, the slow and deliber- 

 ate movements of the skunk and the flapping- or 

 floating flight of conspicuous butterflies must be 



Fig. 2.— Mouse's or cricket's view of the common skunk ; photographed outdoors from a stuffed skin. From 

 "Concealmg-Coloiation in the Animal Kingdom." 



remembered in association with their display and 

 the special protection of which it is an advertist- 

 ment. 



Although I am unable to agree with these and 

 some other conclusions of the authors, and have 

 been obliged to devote so much of the available 

 space to criticism, I should wish ag-ain to em- 



