238 NORTH AMERICAN FAUNA [No. 55 



punctured, and others had bloody noses and damaged tails. Old 

 Hopsy, the first one taken and the gentlest of the lot, was twice 

 rescued from combats with a bloody nose, and between sniffles she 

 kept up a belligerent undertone of chur, chur, chur, and had to be 

 held and comforted for some time to be kept from going back on the 

 warpath. 



There seems to be no age or sex distinction in the fighting, both 

 males and females being attacked indiscriminately by the other. The 

 younger and weaker animals suffer most. In the open where escape 

 is easy the fighting is probably not often serious, but occasionally 

 specimens are taken with ragged ears or injured tails. The fighting 

 instinct is evidently an outcome of the storing habit, each animal be- 

 ing of necessity compelled to protect and defend its food supply. 



Voices. Generally the animals are silent, but close association 

 shows that they have many little sounds and notes that mean dif- 

 ferent things. When disturbed in a nice warm nest, they often make 

 a complaining note. Again, when hopping about the floor at night, 

 a low birdlike chirp, chirp, chirp is occasionally heard, or when on 

 the warpath this note becomes an angry chur, chw, chur, and if two 

 come to blows there are sharp squeaks and squeals, sometimes franti- 

 cally shrill in pain or anger. 



Breeding habits. The females have normally 3 pairs of mammae, 

 2 inguinal on a pair of elongated glands and 1 pectoral on short 

 glands. In 1 female there were also 2 pairs of pectoral mammae. 

 Three and four embryos have been found in females taken for speci- 

 mens in June and July, but the breeding season is probably as irregu- 

 lar and uncertain as in other desert mammals. Apparently no small 

 young have ever been found, and little is known of the breeding 

 habits. 



Food habits. Their food consists largely of seeds of a great vari- 

 ety of plants, including grasses, grains, pigweeds, wild mustards, 

 capers, shadscale, Dondia, wild sunflowers, lupines, and the small 

 desert star Mentzelia albicaulis. In captivity they are fond of rolled 

 oats and any seeds or grains but also eat green leaves of weeds, fresh 

 cabbage, and the rinds of ripe cantaloups. At first they would not 

 touch water but were eager for juicy cabbage and cantaloup, but 

 after a week or more in the house they were noticed drinking the 

 drops of water spilled on the kitchen floor, and when some water 

 was given them in shallow dishes they drank eagerly but in a peculiar 

 way, dipping it up and licking it from the hands, usually both hands 

 together and not from one hand as does Perognathus. In the desert 

 they evidently obtain their water from succulent vegetation, and in 

 the dry season they were found carrying both ripe and green seed 

 capsules of Mentzelia in their pockets. Each of these little green 

 capsules, half an inch long and a tenth of an inch in diameter, con- 

 tains a good-sized drop of clear green juice, not unpleasant in flavor 

 and affording an ample supply of water during the hottest, driest 

 part of the summer,. 



Economic status. In the warm, arid valleys where most of these 

 little kangaroo rats are found there is generally no form of agricul- 

 ture for them to interfere with, but occasionally where dry farming 



