114 



NORTH AMERICAN FAUNA 75 



Orthogeomys heterodus 

 Variable Pocket Gopher, Taltusa 



The variable pocket gopher, a species endemic to Costa Rica, is known from 

 the mid- and high elevations of the Cordillera Central and Cordillera de Talamanca 

 (Fig. 90). Three subspecies of Orthogeomys heterodus currently are recognized 

 from Costa Rica, but we know little of its systematics, distribution, or ecology. 

 The subspecies O. h. cartagoensis occurs on the northeastern Caribbean slope and 

 in the adjacent central valley. Although there are no specimens of 0. heterodus 

 from Braulio Carrillo, this species is known from just outside the park near Con- 

 cepcion de San Rafael de Heredia and elsewhere in Heredia Province, and we 

 suspect that it occurs in the park also. 



In a study of several aspects of the natural history of O. heterodus near Con- 

 cepcion, Sisk and Vaughan (1984) found that variable pocket gophers had exten- 

 sive mnnel systems that consisted of three parts: an enlarged central chamber or 

 nest, radiating tunnels that connect the nest with foraging areas, and a network 

 of shallow feeding tunnels. They found multiple foraging areas within the territory, 

 a foraging strategy previously unreported in pocket gophers. Activity periods con- 

 sisted of short excursions from the nest area to foraging areas, with 90% of the 

 time spent near the nest. The average home range for two gophers was 237 m^ 

 (Sisk and Vaughan 1984). 



Fig. 90. Variable pocket gopher, Orthogeomys heterodus. Photo by N. Woodman. 



