THE COLOURS OF DESERT ANIMALS 163 



nearly all their lives underground : they are certainly 

 paler and less distinctly marked when they Hve 

 in the soil of deserts than when they live in the soil 

 of wooded country, as my friend Capt. C. M. 

 Ingoldby informs me. 



It is generally true that bats of desert areas are 

 paler above and below than their relations living in 

 areas which are not desert. Many examples might 

 be chosen from Persia, Mesopotamia, Egypt, and the 

 American deserts to show that this diiference is the 

 rule. This very general truth hardly admits of an 

 explanation as an example of "protective colora- 

 tion," for predaceous enemies of bats must be rare ; 

 and in any case they do not pursue the bat against 

 a background of desert soil. The most likely 

 enemies are owls, but in the Great Palaearctic Desert 

 owls are on the whole not common, except the Little 

 Owl (Athene noctua subspp.), which hunts in the dusk 

 rather than at night and is not a serious enemy of 

 the bats. From what enemy, then, are the bats 

 " protected," and if a predaceous enemy exists does 

 their protection not He rather in their speed and 

 agility than in their colour ? 



I have endeavoured to show that the theory of 

 protective coloration breaks down when we consider 

 particular animals with reference to their prey or 

 their predatory enemies. There are other instances 

 in which the animal's colour should apparently give 

 perfect protection were it not that its habits are 

 unsuitable. 



One must realize that colour assimilating perfectly 

 to the natural environment will give little protection 



