es, and seldom wander far from home. Although the guinea-pig is a
fertile breeder, the wild species only produce one or two young at a
birth, and this but once in a year. The young come into the world in a
highly developed condition, being able to feed themselves the day
following their birth. Cavies are widely distributed in South America,
and are represented by several species. Among them may be mentioned the
aperea or restless cavy (_C. porcellus_ or _C. aperea_) of Brazil; the
Bolivian _C. boliviensis_, found at great elevations in the Andes; the
Brazilian rock-cavy (_C. rupestris_), characterized by its short blunt
claws; and the Peruvian _C. cutleri_. The latter was tamed by the Incas,
and is the ancestor of the guinea-pig. As to the origin of that name,
some writers consider it a corruption of Guiana-pig, but it is more
probable that the word "Guinea" merely signifies foreign. The guinea-pig
is a singularly inoffensive and defenceless creature, of a restless
disposition, and wanting in that intelligence which usually
characterizes domestic pets, although said to show some discrimination.
It is of no particular service to man, neither its flesh nor its fur
being generally put to use, while the statement that its presence is
sufficient to drive off rats and mice appears to be without foundation.
It is exceedingly prolific, beginning to breed at the age of two months;
the number of young varying, according to the age of the parent, from
four to twelve. It has been calculated that a single pair of guinea-pigs
may prove the parent stock of a thousand individuals in a single year.

A very different animal is the Patagonian cavy, or mara (_Dolichotis
patachonica_), the typical representative of a genus characterized by
long limbs, comparatively large ears, and a short tail. The animal is
about the size of a hare, to which it approximates in form and habits.
It is most abundant in the open districts of Patagonia, but also ranges
on to the Argentina Pampas, where it is now scarce. Although
occasionally seen in large flocks, the mara is more commonly found in
small parties or in pairs, the parties commonly moving in single file.
It has a peculiar kind of hopping gait; and is mainly diurnal, in
accordance with which habit its eyes are protected by lashes. It lives
in a burrow, generally excavated by itself; but when pursued, seeks
safety in flight, rather than by a retreat to its hole. From two to five
young are produced twi