262 



MAMMALS OF AMERICA 



species and subspecies ; and the genus Micro- 

 djpodops, much smaller than either of the other 

 two genera and containing four species. 



The fifth toe of the genus Perodipus is so 

 small that for a long time it was not discovered 

 by the naturalists. Of the five-toed group, one 

 of the best known is Gamhcl's Pocket Rat de- 

 scribed above. One of the largest and hand- 

 somest is Richardson's. According to Bailey, 

 it " fairly revels in the mellow soil of the yel- 

 low, shifting, naked drifts and dunes that the 

 wind piles up along the edges of the river val- 

 leys." It scampers over the smooth surface with 

 the apparent enjoyment of boys on a skating 



turnal animals and rarely seen alive, these Kan- 

 garoo Rats usually make their presence evident 

 by conspicuous mounds scattered here and there 

 over the barest and hardest of gravelly mesas, 

 mounds as characteristic and unmistakable as 

 Musk-rat houses or Beaver dams, and as care- 

 fully planned and built for as definite a purpose 

 — home and shelter. An old mound that has 

 been inhabited for years is often three or four 

 feet high and ten or twelve feet wide. Usually 

 one or more of these doorways are closed each 

 morning with earth behind the retiring inmates, 

 probably to keep out rattlesnakes and other 

 unwelcome guests. The animals are social. 



Photograph by Dr. R. VV. Shufeldt 



RICHARDSON'S KANGAROO RAT 

 A specimen photographed from life, in a Kansas wheat field 



pond ; sometimes it hops but a few inches, but 

 often takes leaps of four to six feet. It makes 

 large burrows, and " they go back horizontally, 

 so that in case of a hard rain the water runs 

 out of instead of into them." Its food is almost 

 entirely seeds, which are always " neatly shelled 

 out and eaten on the spot, or carried in the 

 ample cheek pouches to the dens to be eaten at 

 leisure." Unless the animals become more than 

 usually nvimerous. Bailey considers " their depre- 

 dations too insignificant for consideration." 



The largest of the four-toed species is the 

 Spectacled Pocket Rat, so called because of the 

 peculiar marking around the eyes. Bailey thus 

 describes their habits : " Although strictly noc- 



Often three or four are caught in a mound. 

 When caught in traps or in the hands, the ani- 

 mals struggle violently, but never make a sound 

 or offer to bite." 



Merritt Cary in " A Biological Survey of 

 Colorado " says, " Kangaroo Rats are stated to 

 have been numerous in Colorado some years ago 

 when only small areas were under cultivation. 

 At that time they were very injurious to crops, 

 digging up large quantities of newly planted grain 

 and caching it in their burrows along the sandy 

 margins of the fields, and also feeding exten- 

 sively on tender green stems of wheat. The bur- 

 rows are usually beneath bushes, or in beds of 

 pricklv iiear. and more rarely under the large 



