DALLES POCKET GOPHER y 



mound. In the tunnels, it can travel backward as fast as forward, its 

 thinly haired tail, with a rather blunt tip, acting as a feeler. 



Mounds vary in size from small repair plugs in the mouth of the holes 

 to piles containing more than a bushel of soil (fig. 5) . Where snow per- 

 sists, tunnels are forced through it. These are often filled with excavated 

 dirt, which remains in the form of casts or ropes when the snow dis- 

 appears. In the looser soils gophers may force their way through and 

 seldom make mounds. 



As evidenced by soil mounds, the Dalles pocket gopher is more active 

 in the fall than in the spring. This may be due partly to the relative 

 scarcity of succulent forage during the late season, which makes active 

 burrow extension necessary to obtain food, and partly to the fact that 

 the season's young are also active. The Dalles pocket gopher excavates 

 very little in soil that is wet and soggy, differing in this respect from the 

 Willamette Valley pocket gopher of western Oregon, which sometimes 

 rolls small mud balls out to form mounds. 



When young gophers are slightly more than half-grown they build 

 living quarters of their own by burrowing off from the parent system. 

 At first their mounds appear helter-skelter and are quite small, but after 

 several weeks, they are difficult to distinguish from those of an adult. 



Reproduction 



The principal breeding season of Dalles pocket gophers is spring and 

 early summer, the beginning coinciding with the emergence and devel- 

 opment of spring vegetation. For example, of 32 females examined from 

 May 1 to 10, 1934, 17 were carrying young, 3 had recently given birth to 

 young, and 12 were in breeding condition. Of the many gophers trapped 

 on the study area, none was found to be breeding in late summer or 

 early fall. 



The average number of young, as determined from counts of uterine 

 sacks and scars, was 6.6. The greatest number was 10 and the smallest 5. 

 This checks closely with earlier work by Wight (9), who found an aver- 

 age of 6.5 fetuses per pregnant female. Wight found actual litters of 2, 

 3, and 4 most common. During excavation work in this study one litter 

 of 4 half-grown gophers was uncovered. 



The general rate of increase may be rather low for rodents, but 26 of 

 a group of 97 gophers fall-trapped on the study area were current year's 

 young. The sex ratio of males to females was found to be 1:1.5. The 

 young reproduce the year following birth. 



Feeding Habits 



The gopher is more active at night than during the day, most of the 

 feeding runways being extended then. During spring, summer, and fall 

 it forages both under and above ground; in winter it includes burrow- 

 ing through the snow in its foraging habits. It feeds mainly on surface 

 vegetation in the immediate vicinity of the opened side runways and on 

 fleshy roots and underground stems. Plants near the burrow entrances 

 are cut off, dragged into the runways, and consumed there. Others are 



949015° — 51— 2 



