Pocket-gopher 5()5 



In Manitoba talpoides finds its choicest home-lands on the 

 rich, rolHng, open country of the Assiniboine, and rarely ven- 

 tures far into the woods. 



On all the prairies of western Manitoba this species num- 

 is in maximum numbers. After walking over much of the ^^^^ 

 region and estimating by results the number of Gophers, I 

 set the population at 5 to 10 per acre. The estimate is sus- 

 tained by the following facts supplied me by Louis J. Ohnimus, 

 Superintendent of the Golden Gate Park, San Francisco. 

 In that famous park, one species of Thomomys {T. bottcs) is 

 common and very troublesome. Ohnimus wrote me in 1899 

 as follows: 



" From 1 00 to 300 Gophers are killed every year in the park. 

 About 100 to 150 acres are covered in the killing. The trapping 

 is generally carried on for three or four months of each year. 

 The Gophers are decreasing in number under this drain." 



From this it might be inferred that 2 or 3 Pocket-gophers 

 to the acre was the probable population, but I saw the area in 

 question at the time, and it showed so little Gopher work that 

 evidently the trapping had been succeeding for some time, 

 and the Gopher population was very far below the average. 



In the Golden Gate Park they merely injure the lawns 

 and gardens by throwing up lines of hills over night, but I 

 have seen vast areas in the Sierra, Colorado, Wyoming, Dakota, 

 and Manitoba where walking was most laborious, on account 

 of the number and extreme activity of the Gophers, where 

 indeed a man sank several inches and a horse nearly a foot 

 at each step. I should think therefore that 5 to 10 Gophers 

 per acre was well within their numbers where they abound. 



But they do not abound in all parts of the range, therefore 

 I should take a fifth of the lowest figure for an estimate, and 

 allow for this range of 2,000,000 square miles a total Gopher 

 population of 1,000,000,000. Talpoides is found in about 

 one-tenth of this range, and therefore should be represented by 

 100,000,000 individuals. Probably its numbers do not fall 

 far below this. 



