304 The Naturalist in La Plata. 



them about and cut them up, as his custom is, he 

 accidentally discovers and feasts on the seed : for 

 vizcachas are fond of exercising their teeth on hard 

 substances, such as sticks and bones, just as cats 

 are of " sharpening their claws " on trees. 



Another remarkable habit of the vizcacha, that of 

 dragging to and heaping about the mouth of his 

 burrow every stalk he cuts down, and every portable 

 object that by dint of great strength he can carry, 

 has been mentioned by Azara, Darwin, and others. 

 On the level plains it is a useful habit ; for as the 

 vizcachas are continually deepening and widening 

 their burrows, the earth thrown out soon covers up 

 these materials, and so assists in raising the mound. 

 On the Buenos- Ayrean pampas numbers of viz- 

 cacheras would annually be destroyed by water in 

 the great sudden rainfalls were the mounds less 

 high. But this is only an advantage when the 

 animals inhabit a perfectly level country subject to 

 flooding rains ; for where the surface is unequal they 

 invariably prefer high to low ground to burrow on, 

 and are thus secured from destruction by water; 

 yet the instinct is as strong in such situations as on 

 the level plains. The most that can be said of a 

 habit apparently so obscure in its origin and uses is, 

 that it appears to be part of the instinct of clearing 

 the ground about the village. Every tall stalk the 

 vizcacha cuts down, every portable object he finds, 

 must be removed to make the surface clean and 

 smooth ; but while encumbered with it he does not 

 proceed further from his burrows, but invariably re- 

 tires towards them, and so deposits it upon the 

 mound. So well known is this habit, that whatever 



