SPECIES. 13 



where they are likely to do irreparable injury by girdling young fruit 

 trees and vines. 



As jack rabbits multiply rapidly they often become great pests. 

 They have comj)aratively few natural enemies, and if not held in check 

 by other agencies would doubtless overrun the country. Their undue 

 increase is prevented- ordinarily by lack of food, by unfavorable climatic 

 conditions, or by disease. Many die during unusually severe winters; 

 a cold, wet spring is disastrous to the young, and thousands of young 

 and old perish during the epidemics which occasionally break out among 

 them over large sections of country. Nevertheless, tbey can adapt 

 themselves to circumstances to such an extent as to be able not only 

 to hold their own under most unfavorable conditions, but to increase 

 rapidly whenever food is abundant. 



JJepredations. — The experience of settlers in the San Joaquin Valley, 

 California, along the Arkansas Elver in southeastern Colorado, and 

 in southwestern Idaho has shown that where new land has been culti- 

 vated or irrigated jack rabbits fairly swarm in from the surrounding 

 country, and instead of being driven out by advancing civilization, at 

 first multiply so enormously that radical measures have to be adopted 

 to protect the crops from destruction. 



Some idea of the extent of these injuries can be formed, when it is 

 stated that the damage caused by jack rabbits to the crops in Tulare 

 County, Cal., during a single year has been estimated at $600,000, and 

 one county in Idaho has actually expended more than $30,000 in boun- 

 ties on these pests ! The money spent by individual farmers in the West 

 on rabbit fences and other devices for protecting crops would aggregate 

 a very large sum, which it is imj)ossible even to estimate. But the thou- 

 sands of rabbits destroyed for bounties and the tens of thousands killed 

 in the large hunts and by epidemics seem to diminish the abundance 

 of the species only in localities where a large part of the land is under 

 cultivation and the animals are systematically killed off year after year. 



Jack rabbits are largely used for food and for sport. In a fair race 

 they can outstrip all but the best hounds and can even keep abreast of 

 a railway train running at a moderate speed for some distance. For 

 coursing the native species are considered equal, if not superior, to the 

 Old World hares. Large quantities are shii^ped to market every year 

 as game, and the trade is capable of considerable increase. The skins 

 might also be saved with profit, but the value of jack rabbits, whether 

 for food or for fur, by no means offsets the immense damage which they 

 do to crops. 



SPECIES FOUND IN THE UNITED STATES. 



This group of rabbits is unfortunately in a somewhat chaotic con- 

 dition, and it will be impossible to treat the species satisfactorily until 

 they have been subjected to a thorough revision. A technical discus- 

 sion of their characters and relationships does not come within the 



