86 THE BREEDING OF ANIMALS 



of young born at one birth. This difference is very 

 marked, as between different species, for example, as 

 between the sow and the ewe. A similar difference is 

 likewise to be observed between individuals and families 

 belonging to the same species. In a general way, the 

 number of young carried in the uterus at one time seems 

 to depend upon the size of the animal. Thus the ele- 

 phant, rhinoceros, hippopotamus, giraffe, bison, domes- 

 tic mare and cow, produce one young at a birth. The 

 goat and sheep, while normally producing one offspring 

 at a time, may frequently produce twins and triplets or 

 even a larger number at one birth. 



The hare and rabbit are much smaller than the sheep 

 and are very much more prolific. The wild rabbit pro- 

 duces from four to eight in a litter. The domestic rabbit 

 is more prolific than the wild, often giving birth to eight 

 or ten at one time. 



The lion and tiger in a wild state give birth to two to 

 three cubs, while the domestic cat will sometimes produce 

 as many as nine. The size of the litter in the fox is from 

 four to eight. The number of young in the litter of the 

 domestic dog varies from five to twelve. 



The domestic sow is an exception to the general, rule 

 that smaller species are more prolific. The sow is the 

 most prolific of the more important domestic animals, 

 though not the smallest. The wild sow's litter numbers 

 four or five. The domestic sow produces from seven to 

 twelve, and much larger litters are common. 



The smaller rodents, like the rat and mouse, are char- 

 acterized by large litters. The rat regularly gives birth 

 to twelve or fifteen young at a time and has been known 

 to produce twenty at one birth. The mouse is equally 

 prolific. 



