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V nivt rsity of California Publications in Zoology [Vol. 12 







■Vm* 



Figure 1 

 Photograph of four pocket gophers (Thomomys bottae bottae) as found 

 entrapped in crude oil which had seeped into the gutter from a newly made 

 street in North Berkeley, California. One gopher was still breathing when 

 discovered. Although firm earth extended within six inches of the animal, 

 escape from the sticky oil had proven impossible. 



width prevent gophers from migrating into an orange orchard? And 

 carrying the idea still farther, if a gopher may be entrapped in oil 

 on top of the ground, why may it not be entrapped in the same sub- 

 stance if it is placed in the burrow? The experiment should be tried. 

 It might prove effectual in an attempt to rid new land of these pests, 

 even if it does not prove practicable on a small scale. 



One fact, at least, would appear to minimize the value of oil for 

 this purpose. Two days after application the surface of the oil hardens 

 and small animals are able to cross without danger. On the other 

 hand, its cheapness helps to balance this disadvantage. A thing to be 

 further considered is the undesirable effect of crude oil on the soil. 



The effectiveness of crude oil, or asphaltum, as a trap for animals 

 is demonstrated by the recent findings of great masses of vertebrate 



