Directive Coloration in Animals. 203 
its utmost efficiency. It is, no doubt, often useful also at night, 
whenever there is any disturbance by storm or prowling enemy. 
Thus far, we have had in mind only the ordinary gray birds and 
animals of the plains, upon which the directive coloration is almost 
invariably white. But the principle extends farther. When the 
general coloration is white or light, the directive color is black or 
dark, as in the pelican, white crane, weasel, etc. In some which 
may be gray in summer and white in winter, both white and black 
may be found in close juxtaposition. Ina very few, black seems to 
serve the purpose, even with gray plumage, as in the horned lark 
and some sparrows (?). The principle may include also cases where 
more brilliant tints than those of the white-black series are 
employed. 
Soon after our interest had been awakened in the cases already 
mentioned it was our privilege to examine a large collection of skunks 
which some fortunate trappers had captured. The striking white 
lines on the black ground and their fantastic and very variable forms 
raised again the question, Why? Our idea of directive coloration 
found a new direction for its application, and it readily suggested 
satisfactory answers to the query. Here were animals living con- 
stantly in dusk and darkness. The conspicuous tail, as Belt re- 
marked long ago, may be classed as a warning signal, and therefore 
protective; but why the elaborate white lines and spots? These 
are only useful at shorter distances, and, therefore, presumably to 
fellow-individuals of the same species. We can readily understand 
how they may clearly reveal not only the general position of the body, 
but also its attitude ; and by the individual variations in the breadth 
and continuity of the lines, individuals may recognize one another 
at night, or in their burrows. In short, these directive mark- 
ings are in this case what signal-lights or flags are to vessels and cars, 
Similar reasoning accounts for the markings prevalent in the raccoon. 
badger, chip-munk, and other burrowing animals. So, too, it ac- 
Counts for some of the markings about the heads of the sparrows, 
larks, ducks, and numerous other birds ; also, about the muzzle, 
ears and throat of antelope, deer, hares and other mammals, whether 
protectively colored or not. These markings are more distinct and 
more frequent about the head, because of its greater expressiveness 
and importance. Of course, in this general outlining of our idea we 
need not attempt to classify rigidly particular markings, for some 
