282 ECONOMIC MAMMALOGY 



... It is the especial prey of Lynx, Urocyon and Bassariscus, which, 

 with the owls, keep its ranks thinned until in many places few are left." 

 Baird wood rat (N. micropus) : "food consists of a great variety of 

 green vegetation, especially the juicy flesh of cactus, but mainly of 

 seeds, nuts and fruit. Cactus fruit and the sweet pods of the mesquite 

 bean are extensively eaten." It sometimes becomes exceedingly numer- 

 ous and does some damage. Their abundance then "attracts great 

 numbers of hawks, owls and other enemies," which soon bring the 

 rats to or below their normal numbers. Among the "more deadly ene- 

 mies" are rattlesnakes, bull snakes, black snakes and whip snakes. 



Not only do the "pack rats" or "trade rats" carry off all sorts of 

 articles to their nests, but other wood rats have the same habit, at 

 least to some extent. A nest of the western bushy-tailed wood rat (N. 

 cinerea ocddentalis) contained 35 different kinds of articles, many of 

 which were not used and could not be used by the rats as food. 53 Wood 

 rats also store very large quantities of food when it is plentiful, whether 

 they need it or not. In the vicinity of Magdalena, New Mexico, wood 

 rats store pinyon nuts, and the Mexicans residing in the region take 

 the stored nuts, thus saving themselves the labor of gathering them. 

 Anthony says: "I was told that eight carloads had been sent to the 

 eastern dealers, at that date, and as many more were expected before 

 the end of the season," and that the store taken from the rats "would 

 be renewed within a week and the same rat pay rent, perhaps as many 

 as five or six times during the fall and winter." 54 Guano from the nests 

 of wood rats has been used extensively by florists in the southwestern 

 United States as a fertilizer for ferns and other plants. 55 



Subfamily Micro tinae 



But little seems to be known of the habits of the American lemming 

 mice, genus Synaptoniys, which are confined mostly to bogs and 

 swamps and are not of much economic importance. The contents of 1 1 

 stomachs from Kansas and one from Minnesota consisted of "finely- 

 ground grass and sedge leaves and a few insignificant traces of other 

 green vegetation," but "judging from the habits of related rodents, 

 these animals may occasionally feed upon a variety of bulbs and even 

 insects." 1 



53 Taylor, The wood rat as a collector, Journ. Mammalogy, i, 91-92, 1920. 



64 Anthony, The wood rat as a harvester, Journ. Mammalogy, I, 140-141, 1920. 



65 Streator, Commercial fertilizer from wood rat nests, Journ. Mammalogy, xi, 

 318, 1930. 



1 Howell, Revision of the American lemming mice (genus Synaptomys), N. 

 Amer. Fauna, No. 50, p. 2, 1927. 



