Ch. 20: Biography of the Vizcacha

_(Lagostomus Trichodactylus.)_

The vizcacha is perhaps the most characteristic of the South American
Rodentia, [Footnote: "According to Mr. Waterhouse, of all rodents the
vizcacha is most nearly related to marsupials; but in the points in
which it approaches this order its relations are general, that is, not
to any one marsupial species more than to another. As these points of
affinity are believed to be real and not merely adaptive, they must be
due in accordance with our view to inheritance from a common progenitor.
Therefore wo must suppose either that all rodents, including the
vizcacha, branched off from some ancient marsupial, which will naturally
have been more or less intermediate in character with respect to all
existing marsupials; or, that both lodents and marsupials branched off
from a common progenitor. ... On either view we must suppose that the
vizcacha has retained, by inheritance, more of the characters of its
ancient progenitor than have other rodents."--DARWIN; _Origin of
Species._] while its habits, in some respects, are more interesting than
those of any other rodent known: it is, moreover, the most common mammal
we have on the pampas; and all these considerations have induced me to
write a very full account of its customs. It is necessary to add that
since the following pages were written at my home on the pampas a great
war of extermination has been waged against this animal by the
landowners, which has been more fortunate in its results--or unfortunate
if one's sympathies are with the vizcacha--than the war of the
Australians against their imported rodent--the smaller and more prolific
rabbit.

The vizcachas on the pampas of Buenos Ayres live in societies, usually
numbering twenty or thirty members. The village, which is called
Vizcachera, is composed of a dozen or fifteen burrows or mouths; for one
entrance often serves for two or more distinct holes. Often, where the
ground is soft, there are twenty or thirty or more burrows in an old
vizcachera; but on stony, or "tosca" soil even an old one may have no
more than four or five burrows. They are deep wide-mouthed holes, placed
very close together, the entire village covering an area of from one
hundred to two hundred square feet of ground.

The burrows vary greatly in extent; and usually in a vizcachera there
are several that, at a distance of from four to six feet from the
entrance, open into large circular chambers. From these chambers other
burrows diverge in all directions, some running horizontally, others
obliquely downwards to a maximum depth of six feet from the surface:
some of these burrows or galleries communicate with those of other
burrows. A vast amount of loose earth is thus brought up,