102 ACQUIRED CHARACTERS sec. 



as in foxes, to which they also approximate in colouring, so 

 that in three or four years they deteriorate into very -agly 

 creatures, and after three or four generations their bark 

 becomes a howl (Bosmann). In Paraguay the domestic cat 

 has become one-fourth smaller, its body is slender, its hair 

 short, shiny, thin, and pressed closely to the skin, especially 

 on the tail, which is almost naked (Eengger). 



In the Malay Archipelago, and in Further India, the cats 

 have a stumpy tail of only half the usual length, and often a 

 kind of knob at the end of it (Crawfurd). 



Also dogs in the tropics, according to several authorities, 

 often become thin haired. 



The regular summer and winter changes of the hair in 

 mammals are supposed by Darwinian reasoning to have been 

 gradually acquired by selection, no thought being given to 

 the ultimate causes of the phenomenon. But the facts above 

 stated seem to indicate that these causes are to be found in 

 the direct influence of climate, or rather in the changes in the 

 physiological condition of the skin produced by climate. 



The fact that our mammals acquire a thinner coat of hair 

 in spring, a thicker coat in autumn, might also be due to 

 another cause, namely, that they are as a rule in a better 

 condition' of nutrition in autumn than in spring. In that 

 case the changes of hair in our domesticated animals w^ould 

 be an inherited acquired character. 



In Porto-Santo the rabbits which have there run wild have 

 on the back red hair only occasionally mixed with black, or 

 black tipped hair. The throat and certain parts of the lower 

 surface are, instead of pure white, pale gray or lead 

 colour, the upper side of the tail reddish brown instead 

 of dark gray, the ears without a blackish border. In less 

 than four years a specimen imported into England from 

 Porto- Santo almost entirely lost the peculiarities of the race 

 (Darwin). 



