CHIPMUNKS 193 



succeed. If swiftness be a point of advantage to the species, then a sort 

 of sexual selection by which swiftness will become an accentuated trait, 

 will here be operative. 



There is always more or less competition between the members of a 

 species in the struggle for existence, and considerable individuality in 

 behavior is exhibited whenever several animals of any one species are 

 gathered at close quarters, as when they are attracted by a common food 

 supply. This individuality was illustrated at Tuolumne Meadows one 

 afternoon in late September, when several Alpine Chipmunks were seen 

 contesting with one another for possession of some scraps of bread which 

 had been discarded from a lunch. At first but one chipmunk was in 

 evidence and he busied himself with a piece of the bread. He was soon 

 observed by another of his kind who shortly arrived on the scene, and 

 this second animal made an attempt to gain possession of the piece held 

 by the first. Being unsuccessful, the second then found another fragment 

 for himself. Later a third and then a fourth chipmunk arrived. Only 

 one animal would eat at any particular piece at one time ; if another 

 attempted to join in, a contest would ensue. Sometimes the original pos- 

 sessor successfully defended his rights, sometimes the interloper gained 

 control. Just as among human beings, one, for the time, might dominate 

 the group, another might be bullied about by all, and the others would 

 hold their ground between these two extremes. 



In spite of the seemingly barren appearance of its chosen habitat the 

 Alpine Chipmunk finds, at the proper season, an abundance of food in 

 the way of ripe seeds. But the season of harvest is short and many of 

 the seeds are of very small size ; to secure these seeds in adequate quantity 

 both for immediate use and for storage therefore requires a rare concen- 

 tration of effort and a high degree of industry on the part of the harvesters. 

 This industriousness is fully apparent if a person takes the time to watch 

 the animals from a vantage point where his presence does not, through 

 fear or alarm, distract the attention of the chipmunks. Analyses of 

 cheek-pouch contents are instructive in this connection also ; and the 

 following selections seem worth placing on record here. 



(1) Fletcher Creek at 10,000 feet altitude, September 4: some fragments of a brown 



fungus. 



(2) Colby Mountain at 9200 feet, October 9: two seeds of pine (thought to be silver 



pine). 



(3) Ten Lakes at 9200 feet, October 8: 47 seeds of a grass (stipa). 



(4) Ten Lakes at 9200 feet, October 11: 324 seeds of sedge and 1 of stipa. 



(5) McClure Fork at 9200 feet, August 29: 165 seeds of sedge and 24 of galingale; 



total 189. 



(6) Mount Hoffmann at 10,300 feet, June 30 : 388 seeds of sedge and 1 of pussy-paws. 



(7) Mount Florence at 10,500 feet, August 21: 1113 seeds of willow-herb, 1 of pussy- 



paws, 19 of stipa, 36 of galingale; total 1169 seeds. 



