312 Problems of Organic Adaptation 



and ragged processes so like sea-weed that it is very difficult 

 to distinguish them from the weed. Certain animals, such as 

 the stick insect, dead-leaf butterfly, and bark spider are so 

 much like the objects on which they are commonly found, 

 both in form and color, that it is difficult to detect them 

 even when searching for them. Other common forms of 

 camouflage are found in "feigning death," or rather in re- 

 maining perfectly quiet to escape detection, for moving ob- 

 jects even though they have concealing colors or forms are 

 much more readily seen than those that remain motionless. 



The use of a "false flag," which has been so much con- 

 demned in human warfare, has apparently been resorted to 

 by animals in certain instances. Such sailing under false 

 colors is known in zoology as "mimicry." Insects that are 

 protected by nauseous odors or by other means are some- 

 times mimicked in form, color, and peculiarities of posture 

 or locomotion by other insects not closely allied to them. 

 Snakes that are non-poisonous sometimes mimic poison- 

 ous ones in forms, colors and threatening attitudes. But in 

 zoology it is almost as difficult to establish the use of a false 

 flag as it is in naval warfare, and it may be that two different 

 species have independently developed similar flags so that 

 neither is "mimic" or "mimicked." 



Electrical fishes, such as the electric eel and the torpedo, 

 are able to generate a strong charge of electricity with which 

 they can shock and stun their enemies or their prey. Of 

 course submarines and flying machines are an old story in 

 animal life, and even smoke screens, or what correspond to 

 these, are used by the squid and other cephalopods which in 

 fleeing from enemies throw out a cloud of ink which conceals 

 them. These modern methods of human warfare have been 

 used for millions and even hundreds of millions of years by 

 lower animals. 



