Biography of the Vizcacha. 303 



the vizcachas cut down every tall plant they can. 

 I have seen whole acres of maize destroyed by them, 

 yet the plants cut down were left untouched. If 

 posts be put into the ground within range of their 

 nightly rambles they will gnaw till they have felled 

 them, unless of a wood hard enough to resist their 

 chisel-like incisors. 



The strongest instinct of this animal is to clear 

 the ground thoroughly about its burrows; and it 

 is this destructive habit that makes it necessary for 

 cultivators of the soil to destroy all the vizcachas 

 in or near their fields. On the uninhabited pampas, 

 where the long grasses grow, I have often admired 

 the vizcachera ; for it is there the centre of a clean 

 space, often of half an acre in extent, on which 

 there is an even close-shaven turf : this clearing is 

 surrounded by the usual rough growth of herbs and 

 giant grasses. In such situations this habit of 

 clearing the ground is eminently advantageous to 

 them, as it affords them a comparatively safe spot 

 to feed and disport themselves on, and over which 

 they can fly to their burrows without meeting any 

 obstruction, on the slightest alarm. 



Of course the instinct continues to operate where 

 it-, is no longer of any advantage. In summer, when 

 the thistles are green, even when growing near the 

 burrows, and the giant thistle (Carduus mariana) 

 springs up most luxuriantly right on the mound, 

 the vizcachas will not touch them, either disliking 

 the strong astringent sap, or repelled by the thorns 

 with which they are armed. As soon as they dry, 

 and the thorns become brittle, they are levelled ; 

 and afterwards, when the animal begins to drag 



