10 The Naturalist in La Plata. 
which it can traly be said that it is in any special 
way the product of the pampas, or, in other words, 
that its instincts are better suited to the conditions 
of the pampas than to those of other districts. As 
a fact, this large rodent inhabits a vast extent of 
country, north, west, and south of the true pampas, 
but nowhere is he so thoroughly on his native heath 
as on the great grassy plain. There, to some extent, 
he even makes his own conditions, like the beaver. 
He lives in a small community of twenty or thirty 
members, in a village of deep-chambered burrows, 
all with their pit-like entrances closely grouped 
together ; and as the village endures for ever, or for 
an indefinite time, the earth constantly being brought 
up forms a mound thirty or forty feet in diameter ; 
and this protects the habitation from floods on low 
or level ground. Again, he is not swift of foot, and 
all rapacious beasts are his enemies; he also loves 
to feed on tender succulent herbs and grasses, to 
seek for which he would have to go far afield among 
the giant grass, where his watchful foes are lying 
in wait to seize him; he saves himself from this 
danger by making a clearing all round his abode, 
on which a smooth turf is formed; and here the 
animals feed and have their evening pastimes in 
comparative security: for when an enemy ap- 
proaches, he is easily seen; the note of alarm is 
sounded, and the whole company scuttles away to 
their refuge. In districts having a different soil 
and vegetation, as in Patagonia, the vizcachas’ 
curious, unique instincts are of no special advantage, 
which makes it seem probable that they have been 
formed on the pampas. 
