hough it may be that they also
occasionally feast on a tender young pup.

The magnificent little animals known to scientists as vizcachas, and
whose homes are on the pampas of South America, are the most skilled
builders of underground cities in the animal world. Their villages or
cities are called "vizcacheras" and are provided with from ten to twenty
mouths or subway entrances, with one entrance often serving for several
holes. If the ground is soft, it is not uncommon to find twenty to
thirty burrows in a vizcachera; but if the ground is rocky and hard,
only four or five burrows are found. These wide-mouthed, gaping burrows
are dug close together, and the entire town usually covers from one
hundred to two hundred square feet.

The vizcacheras are different from other underground animal cities; some
of the burrows are large, others are small. Most of them open into a
subterranean main-street at from four to six feet from the entrance;
from this street other streets wind and turn in all directions, like a
man-made subway, and many of them extend clear into other streets or
subways, thus forming a complete network of underground passageways. All
the tunnelled-out dirt is brought to the surface and forms a large mound
to prevent the water from entering the cities.

According to W. H. Hudson, in _The Naturalist in La Plata_, "in some
directions a person might ride five hundred miles and never advance half
a mile without seeing one or more of them. In districts where, as far as
the eye can see, the plains are as level and smooth as a bowling-green,
especially in winter when the grass is close-cropped, and where the
rough giant-thistle has not sprung up, these mounds appear like brown or
dark spots on a green surface. They are the only irregularities that
occur to catch the eye, and consequently form an important feature in
the scenery. In some places they are so near together that a person on
horseback may count a hundred of them from one point of view."

Unlike some burrowing animals, the vizcacha does not select a spot where
there is a bank or depression in the soil, or roots of trees, or even
tall grass; knowing that they only attract the opossum, skunk,
armadillo, and weasel, he chooses an open level plot of ground where he
can watch in all directions for enemies while he works.

The great or main entrance to some of these underground cities is
sometimes four to six feet in diameter. A small man stands shoulder dee