138 AXIMAL LIFE I.\ THE YO SEMITE 



short distance. Many times gophers tunnel toward the surface beneath 

 plants and cut off roots and even the main stems, without causing any 

 disturbance above ground until the plant begins to wither and die. 



"When excavating, gophers loosen the earth with their strong incisor 

 teeth and the long claws of the forefeet (pi. 29c). The earth thus loosened 

 is swept back underneath the body until a considerable amount has accumu- 

 lated. The animal then turns around (being able to do so within the 

 diameter of its own body), and pushes the earth along the tunnel to a 

 surface opening where it is shoved out on top of the ground. (See pi. 296 

 and fig. 23.) Only the forefeet, in conjunction with the broad furry face 

 below the level of the nose, are used in moving the earth; the outside- 

 opening cheek pouches (pi. 27&) w^th which the animal is provided, and 

 which open at either side of the mouth, are used for the sole purpose of 

 carrying food material. After tunnel excavation has proceeded a few 

 inches beyond one surface opening, the opening is closed and a new opening 

 made at a more convenient position, nearer the spot where earth is being 

 removed. Most of the surface openings are at the ends of side tunnels 

 which are but a few inches in length. Sometimes a great quantity of earth 

 is pushed out at one surface opening. One mound observed in the Ten 

 Lakes basin was 25 inches (621/2 cm.) in diameter at the base and 6 inches 

 (15 cm.) high; the total earth pushed out amounted to 7825 cubic inches, 

 or about four and one-half cubic feet (123,705 cc). 



Gophers at the higher altitudes show most activity during the late after- 

 noon and early evening hours. It is then that most new mounds are to be 

 seen and that trapping is most successful. In high meadows where there 

 is a heavy frost, the surfaces of mounds made during the night are usually 

 frozen stiff by morning, showing that the mounds were piled up before the 

 nightly drop in temperature. However, especially in lower altitudes, 

 gophers work a good deal in the morning and do some work at almost any 

 hour of the day. 



With regard to breeding habits in the Yosemite, we have little to report 

 save what is shown by the specimens captured. We did not in any instance 

 try to dig out the home burrows, A quarter-grown juvenal {pascalis) 

 taken at Snelling January 5, 1915, indicates early breeding at that low 

 altitude (250 feet). A female (mciva) taken at Pleasant Valley, May 21. 

 1915, contained four large embrj'os. Two young (mouiwola), one-cjuarter 

 to one-third grown, were taken at Mono Meadow on June 18, 1915. Five 

 pregnant gophers (monticoJa) were taken in 1915 at the higher altitudes: 

 Porcupine Flat, June 28, 6 large embryos; same locality. July 1, 5 small 

 and 7 small; same locality, July 2, 3 embryos; Tuolumne Meadows, July 11. 

 5 embryos. 



