WOOD-RATS, PACK-RATS, ETC. 111 
on entering the burrow before daylight in the 
morning they securely close the opening behind 
them by packing it full of fresh sand, doubtless 
to keep out snakes, weasels, and other unwel- 
come intruders. 
Their food consists mainly of the small seeds 
of native desert plants, but also includes a little 
grain. A part of the food is carried into their 
burrows for future use. They are never suffi- 
ciently abundant to seriously injure crops, but 
a year or two ago were found damaging vine- 
yards in the Santa Cruz Mountains, California, 
by biting off fruit-buds. The trouble was easily 
disposed of by scattering poisoned grain near 
their burrows. This course will always free a 
locality from them whenever they may become 
a little harmful. . 
