Richardson Ground-squirrel 385 



where there may not be another Gopher, for miles perhaps, 

 we come upon a soHtary individual guarding a well-used bur- 

 row, all alone in his glory. The several such animals 1 have 

 shot all proved to be males; and what is singular, these old 

 fellows are always larger than the average (some would weigh 

 twice as much), peculiarly sleek and light-coloured, and enor- 

 mously fat. The earlier ones I got I suspected to be a differ- 

 ent species, so peculiar were they in many respects. I suppose 

 they are surly old bachelors who have foresworn society for a 

 life of indolent ease, though if I had found them oftener among 

 their kind I should have taken them for the Turks of the 

 harem." 



The species utters a husky alarm whistle as soon as it inter- 

 scents danger, and the end of the tail is raised at each whistle; nica". 

 thus we have directive sounds and marks combined. Old ^^°^ 

 plainsmen say that a Prairie-dog's voice is tied to its tail, be- 

 cause every time it lifts one it lifts the other, and when one 

 stops the other does. This is equally true of the present 

 species. 



It is not known whether this rodent pairs, is polygamous, matixg 

 polyandrous, or promiscuous. The mating season is about 

 the middle of April or before that. Francis Dickie writes me 

 from Carberry that on April 21, 1905, he killed 11 Yellow- 

 gophers; of these 6 were females, and 4 pregnant; the embryos 

 very small except in one case, where they were each half an inch 

 long. 



Three females taken April 29 showed embryos from the 

 size of No. 4 shot (3-16 of an inch) to that of a bean (7-16 of an 

 inch). 



TION 



As the gestation of the rat is 21 days, and that of the rab- gesta- 

 bit 30 days, it is likely that the Ground-squirrel's period is 

 between the two; therefore the first of these embryos was in 

 the second week of development and the last within ten days 

 of birth. 



