294 ECONOMIC MAMMALOGY 



quire the rat-proofing of all buildings, not only as a sanitary measure, 

 but also to prevent them from becoming breeding places for rats. 

 Silver, in the preface to a recent bulletin, says: "When rat-proofing 

 becomes the regular practice the rat problem will have been largely 

 solved." 9 



The house rat as a disseminator of bubonic plague has been dis- 

 cussed in Chapter xm. Introduced into Japan, these rats at ebb tide 

 "enter into sea water and capture shells, as well as small fishes, etc." 10 



In view of all that has been said against the brown rat, it is refresh- 

 ing to record an item in its favor. One is reported to have killed a 

 rattlesnake. 11 



FAMILY APLODONTIDAE MOUNTAIN BEAVERS 



The genus Aplodontia ranges from northern California to British 

 Columbia. Their summer food is mostly green vegetation, "practically 

 everything the season affords," and they do some damage to vegetable 

 gardens. Their winter food is mostly bark, and in girdling trees they 

 cause more or less injury. In their storehouses in the Puget Sound 

 Basin 32 different kinds of plants have been found. In some places 

 their burrows damage roads. 1 Their habit of "hay-making," or gather- 

 ing, piling up apparently to dry, and storing vegetation, a habit shared 

 with the pikas, has led to a difference of opinion. One author says that 

 the material is used only for nest building, perhaps overlooking the 

 fact that their summer food, green vegetation, is not available in the 

 winter. 2 



FAMILY ZAPODIDAE JUMPING MICE 



Prairie jumping mouse (Zapus hudsoni campestris) : many stomachs 

 examined, contained only seeds, usually of grasses, but some seeds of 

 other plants and grain. 3 Usually not abundant enough to do harm. 



FAMILY ERETHIZONTIDAE AMERICAN PORCUPINES 



The summer food of the North American porcupines (Erethizon) 

 consists of almost any green vegetation available, including alfalfa and 



9 Silver, Rat-proofing buildings and premises, Farmers' Bull. No. 1638, 1930. 



10 Kuroda, Journ. Mammalogy, in, 44, 1922. 



11 Hartman, A brown rat kills a rattler, Journ. Mammalogy, in, 116-117, 1922. 



1 Scheffer, Mountain beaver in the Pacific Northwest : Their habits, economic 

 status and control, U. S. Dept. Agric. Technical Bull., No. 1598, 1929. Taylor and 

 Shaw, Mammals and birds of Mount Rainier National Park, pp. 86-87, 1927. 



2 Seton, Lives of game animals, iv, Part 2, pp. 526-555, 1929; citing Nelson, Wild 

 animals of North America, pp. 532-533, 1918. Camp, Excavation of the burrows of 

 the rodent Aplodontia, etc., Univ. California Pub. Zool, xvn, No. 18, pp. 517-536, 

 1918. 



3 Bailey, N. Amer. Fauna, No. 49, p. 117, 1926. 



