116 The Pocket Gopher. 



ness of his tunnels. In watching gophers push out the earth 

 when extending their burrows I have never seen one expose 

 more of the body than the head, and usually one can catch a 

 glimpse of the nose only, as with a quick upward flirt of this 

 member the animal flings the dirt from the exit. As the earth 

 is sometimes pushed to a considerable distance from the tempo- 

 rary opening, it is likely that the gopher must of necessity 

 emerge entirely from his burrow at times. This he no doubt 

 does under cover of darkness, for it is a matter of common 

 observation that after a busy hour or so in the early morning 

 very little dirt flies again until near sunset, except perhaps on 

 dark, cloudy days. No evidence of tracks or traces of foraging 

 indicates that the animal ordinarily ventures farther than its 

 mound of earth, however, even in the night. At certain sea- 

 sons, though, particularly when many of the young genera- 

 tion of that year are setting up in business for themselves, the 

 natural instinct of all animals to extend the limits of their 

 range impels the gopher to roam about. This is evidenced by 

 the sudden appearance in late summer and in autumn of new 

 mounds, like pioneer shanties, in fields remote from other 

 gopher habitations. At this season we occasionally encounter 

 a claim seeker abroad even in the daytime. In late autumn 

 and early winter, too, the males no doubt wander about more 

 or less. 



The; Burrow. Except where an invader has recently estab- 

 lished himself in new territory, it is practically impossible to 

 determine the limits of a gopher's burrow. The work of ex- 

 cavating is usually carried on at a depth of eight to ten inches 

 below the surface of the ground, but the animal sometimes 

 ranges lower in loose, sandy soil where succulent roots pene- 

 trate deeper. The average diameter of the burrow of the 

 prairie pocket gopher is about three inches ; large enough that 

 one may usually thrust the hand and arm back into it as far 

 as he can reach. These data are easily obtained ; but when one 

 undertakes to map out the course of the main runways, the 

 branch tunnels and their intersections, the pockets and the 

 short laterals, he has before him a task that might well appal 

 a military engineer in the wilds of a jungle. In a field that is 

 even fairly well populated by gophers the runways of different 

 individuals must of necessity frequently intersect each other, 

 for it cannot be supposed that all the numerous subway cross- 



