SEPARATION OF SEXES 103 



four weeks or months of pregnancy, the violent 

 efforts required from them in contests with competi- 

 tors and enemies, or in attempts to escape from them 

 by flight, must daily have become more difficult of 

 execution, more barren of success, more productive 

 of painful and distressing symptoms to the females, 

 until the limits of endurance were reached. At this 

 point the victims, under an overwhelming sense of 

 their desperate helplessness, would be unable to 

 prevent their natural intrepidity from giving way 

 to a supreme desire for seeking safety by hiding. 

 For this impulse had been increasing, pari passu, 

 with their helplessness. A tendency to hide during 

 the last stages of pregnancy under conditions then 

 existing, obviously had great survival value. After 

 coming into existence, either in the manner above 

 outlined or in any other, it would, therefore, gain 

 strength and fixity by natural selection. The va- 

 lidity of the above arguments is not affected by any 

 assumed brevity or length of the female's period of 

 incapacity, whether it lasted days, weeks, or months, 

 nor by the degree of it. The unavoidable admission 

 of some impairment of their full vigor, for a brief or 

 long period, is sufficient to sustain them. 



Conditions similar to those above alluded to, 

 which made the hiding habit of the pregnant females 

 a necessity in the primeval era of the human race, 

 do not exist in the case of the anthropoid apes. It 

 is true that these creatures can stand and move 

 about in an almost erect attitude. However, they 



