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 vizeacha, 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 
