Biography of the Vizcacha. 297 



dry mound of soft earth which the vizcacha elevates 

 amidst a waste of humid, close-growing grass is not 

 absolutely necessary to the existence of all these 

 species, it supplies them with at least one favourable 

 condition, and without doubt thereby greatly in- 

 creases their numbers : they, too, whether preda- 

 cious or preyed on, have so many relations with 

 other outside species, and these again with still 

 others, that it would be no mere fancy to say that 

 probably hundreds of species are either directly or 

 indirectly affected in their struggle for existence by 

 the vizcacheras so abundantly sprinkled over the 

 pampas. 



In winter the vizcachas seldom leave their bur- 

 rows till dark, but in summer come out before 

 sunset ; and the vizcachera is then a truly interest- 

 ing spectacle. Usually one of the old males first 

 appears, and sits on some prominent place on the 

 mound, apparently in no haste to begin his evening 

 meal. When approached from the front he stirs 

 not, but eyes the intruder with a bold indifferent 

 stare. If the person passes to one side, he deigns 

 not to turn his head. 



Other vizcachas soon begin to appear, each one 

 quietly taking up his station at his burrow's mouth, 

 the females, known by their greatly inferior size 

 and lighter grey colour, sitting upright on their 

 haunches, as if to command a better view, and in- 

 dicating by divers sounds and gestures that fear and 

 curiosity struggles in them for mastery ; for they 

 are always wilder and sprightlier in their motions 

 than the males. With eyes fixed on the intruder, 

 at intervals they dodge the head, emitting at the 



