THEIR RELATION TO ANIMALS 131 



Among animal feeders on insects we may enu- 

 merate toads, frogs, snakes, lizards and all their rela- 

 tives; the tortoises generally; rats and mice and their 

 allies; the shrews and their allies ; bats, coons, opossums, 

 moles and, to a less extent, the larger carnivora. The 

 smaller species of the cat and dog tribe eat a large 

 number of insects and even bears count them among 

 their list of eatables. Fish eat the aquatic species when- 

 ever they can get at them, and birds have been already 

 referred to. Now, when we realize that the insecti- 

 vores among the mammals form a very numerous 

 and important series, and that the carnivores assist, 

 we get at once a formidable list of destroyers against 

 which, as already stated, the insects have little defence. 

 The matter of protective resemblance of course comes 

 in; but that plays really a very subordinate part. 

 There is no doubt that many insects resemble their 

 surroundings so closely that they are with difficulty 

 to be seen; but they can be seen by the trained eye. 

 Some species of moths sit openly on the tree trunks 

 in city streets and hundreds of passers-by absolutely 

 fail to see them; but to the first entomologist that 

 comes along they are as obvious as if they had been 

 placed there to attract his attention. It would be 

 ranking bird and animal senses very low indeed if we 

 seriously believed that such resemblances made them 

 actually invisible to those who have in hunger the 

 best sharpener for the senses that can be imagined. 

 That such resemblances do protect from casual ma- 

 rauders there is little doubt, and that there is a better 

 chance of escape from a casual search than there would 

 be were the insects more conspicuous we may assume; 

 but that the resemblance is protective to the extent that 

 is sometimes claimed is at least open to serious doubt. 



"Playing possum" is a much better protection, 



