THE RABBIT. 131 



farmers caused by rabbits in ten years ia the single 

 province of New South Wales, was $15,000,000. 



Likewise, in some parts of California, rabbits have 

 become a pest. 



Any animal, no matter what it is, unless. killed by 

 some other means than a natural death from old age, 

 will multiply so rapidly as to eat up all the food that 

 a country can furnish, and so exclude or drive out all 

 other animals that depend upon the same kind of food. 

 The rabbit is preyed upon by other animals, it is frozen 

 to death in winter, and it is starved in snowdrifts, or 

 when its food is all covered with snow ; but the rains 

 in the spring afford, probably, the most efficient check 

 upon the number of rabbits in the greater part of the 

 United States. 



Rabbits produce seven to Jiine young at a birth, 

 and usually in the early spring. The young are com- 

 monly born in a bed made in a shallow depression in 

 the ground. If a heavy, dashing rain comes about the 

 time that the young are in this form, it is very prob- 

 able that all or nearly all will be drowned. 



Rabbits and other animals are subject to various 

 diseases which operate as checks upon their rate of 

 increase. The tapeworm is a very common parasite 

 among rabbits. In one lot of ten dozen rabbits exam- 

 ined by the writer, forty-two were found to be infested 

 with tapeworm. This, however, is a very large per- 

 centage to be so infested. 



Sometimes, when an animal or a plant is carried 

 from one country to another, the diseases, enemies, or 

 other checks that prevented its rapid increase at home 

 are not carried with it. Being freed from the checks 

 that restrained it at home, it multiplies so rapidly as to 

 become a serious evil. Such is probably the case with 

 the gypsy moth mentioned on page 37. Such is the 

 case with the San Jose scale insect, which has been very 

 destructive to orange groves in California. In such a 



