290 SEXUAL SELECTION: MAMMALS. [Part II. 



intermediate in certain osteological characters between 

 the pachyderms and ruminants, which were formerly 

 thought to be quite distinct. 41 



A curious difficulty here arises. If we admit that col- 

 ored spots and stripes have been acquired as ornaments, 

 how comes it tjiat so many existing deer, the descendants 

 of an aboriginally spotted animal, and all the species of 

 pigs and tapirs, the descendants of an aboriginally striped 

 animal, have lost in their adult state their former orna- 

 ments ? I cannot satisfactorily answer this question. We 

 may feel nearly sure that the spots and stripes disap- 

 peared in the progenitors of our existing species at or near 

 maturity, so that they were retained by the young, and, 

 owing to the law of inheritance at corresponding ages, by 

 the young of all succeeding generations. It may have 

 been a great advantage to the lion and puma, from the 

 open nature of the localities which they commonly haunt, 

 to have lost their stripes, and to have been thus rendered 

 less conspicuous to their prey;*and if the successive vari- 

 ations, by which this end was gained, occurred rather late 

 in life, the young would have retained their stripes, as we 

 know to be the case. In regard to deer, pigs, and tapirs, 

 Fritz Muller has suggested to me that these animals, by 

 the removal through natural selection of their spots or 

 stripes, would have been less easily seen by their enemies ; 

 and they would have especially required this protection, 

 as soon as the carnivora increased in size and number 

 during the Tertiary periods. This may be the true ex- 

 planation, but it is rather strange that the young should 

 not have been equally well protected, and still more 

 Btrange that with some species the adults should have 

 retained their spots, either partially or completely, during 

 part of the year. "We know, though we cannot explain 



41 Falconer and Cautley, ' Proc. Geolog. Soc' 1843 ; and Falconer's 

 Pal. Memoirs,' vol. i. p. 196. 



