o found a new
community, for they increase very slowly, and are very fond of each
other's society. It is invariably one individual alone who founds the
new village. If it were for the sake of better pasture he would remove
to a considerable distance, but he merely goes from forty to sixty
yards off to begin operations. Sooner or later, perhaps after many
months, other individuals join the solitary Vizcacha, and they become
the parents of innumerable generations in the same village: old men,
who have lived all their lives in one district, remember that many of
the Vizcacheras around them existed when they were children.

It is always a male who begins the new village. Although he does not
always adopt the same method, he usually works very straight into the
earth, digging a hole twelve or fourteen inches wide, but not so deep,
at an angle of about 25 deg. with the surface. After he has progressed
inwards for a few feet, the animal is no longer content merely to
scatter the loose earth; he cleans it away in a straight line from the
entrance, and scratches so much on this line, apparently to make the
slope gentler, that he soon forms a trench a foot or more in depth,
and often three or four feet in length. This facilitates the
conveyance of the loose earth as far as possible from the entrance of
the burrow. But after a while the animal is unwilling that earth
should accumulate even at the end of this long passage, and proceeds
to form two additional trenches, making an acute or right angle
converging into the first trench, so that the whole when completed
takes a Y shape. These trenches are continually deepened and
lengthened in this manner, the angular segment of earth between them
being scratched away, until by degrees it gives place to one large
deep irregular mouth. The burrows are made best in the black and red
moulds of the pampas; but even in such soils the entrances may be
varied. In some the central trench is wanting, or so short that there
appear to be but two passages converging directly into the burrow, or
these two trenches may be so curved inwards as to form the segment of
a circle. Usually, however, the varieties are only modifications of
the Y-shaped system.

On the pampas a wide-mouthed burrow possesses a distinct advantage
over the more usual shape. The two outer trenches diverge so widely
from the mouth that half the earth brought out is cast behind instead
of before it, thus creating a mound of equal