146 ANIMAL COMPETITOES 



straight down in a narrow shaft below the frost 

 line, then turns and winds away horizontally, 

 and as the tunnels are used year after year, 

 with continual enlargements, old ones may 

 reach to a great length, with branches and 

 chambers accommodating several pairs, and 

 secret exits. In the autumn one of the under- 

 ground chambers is furnished with soft bedding 

 and becomes the living-room of a family, while 

 other chambers are stored with provender or 

 set apart as receptacles for refuse. Now the 

 chipmunk becomes exceedingly busy, fattening 

 himself upon the ripening nuts and seeds, not 

 only, but upon many tuberous roots, mushrooms 

 and green corn. On each side of his mouth, 

 separated from it by thin partitions of muscu- 

 lar skin, are large cavities or pouches, opening 

 behind the teeth, which are as useful to him as 

 are our baskets and wheelbarrows to us. He 

 brings to the surface in them the material ex- 

 cavated from the distant ends of his burrow, 

 and after packing them full of seeds or nuts he 

 returns to empty their loads perhaps half a 

 pint at a time in one of his storehouses. All 

 the ground-squirrels have such cheek-pouches; 



