6 INTRODUCTION TO SEXUAL PHYSIOLOGY 



Tlic following are the average periods of gestation among the 

 common domestic animals : — Mare, 11 months ; cow, 9 months ; 

 ewe, 21 to 22 weeks or about 5 months ; sow, 112 to 116 days 

 or about 4 months ; bitch, 60 to 63 days ; cat, 56 to 63 days ; 

 rabbit, 30 days ; guinea-pig, 62 days ; tame rat, 21 days. 

 Prolonged gestation is not infrequent in animals as well as in 

 man. In rodents it may be associated with the suckling of a 

 previous litter. 



