THE order of animals to which the well known and widely distributed Rats
and Mice belong, is a very large one, including animals that are
adapted, according to the genus, either for running, jumping, climbing,
flying or swimming. They are armed with sharp claws, enabling them to
climb trees or burrow in the earth. But the special characteristic of
all the animals of this group, is that they possess only two kinds of
teeth—incisors and molars. The incisors, two in number, in front of each
jaw, are very remarkable. Their office is to cut, as with shears, roots
and branches, and they are wonderfully constructed for this purpose.
These teeth are long, stout and curved, and being covered with enamel on
their front face only, they wear away more behind than in front; and by
rubbing one against the other naturally form a bevelled edge. They
therefore keep a hard edge that is always sharp-cutting, ready for
sawing through or gnawing tough substances.
Another strange thing about these teeth is that they always keep the
same length, notwithstanding their continual wear. The fact is, they
have no roots, and grow from the base in the same proportion as they are
worn away at the top.
Many of the Gnawing Quadrupeds have their hind limbs much larger than
the front ones, so that they leap rather than walk, giving them the
appearance of the Kangaroo and others belonging to the Marsupial family.
The animals of the Rodent order feed mainly on seeds, fruit, leaves,
grasses and occasionally on roots and bark. Some of them, however, such
as the Rat, are omnivorous, and will even eat flesh.
A great number of the Rodents have their bodies covered with fine, soft
and prettily-colored hair. For instance, the small Grey Squirrel and the
Chinchilla both furnish furs of value; and the coats of the Beaver and
the Rabbit are used in some of our manufactures.
The Rodents are not usually divided into very distinct families, as
their natural characteristics are not clearly marked. In the family of
Rats and Mice a large number may be grouped. These form the Mus species,
from the Latin, Mus, meaning Mouse or Rat. The most of the members of
this family are too well known to require more than mere mention. This
family includes besides what are known as the Rats and Mice proper, the
Field Rats and Mice, the Dormice, Ondatras, Musquash or Musk Rats,
Lemmings, Hamster Rats and Jerboa Rats.
Grouped with the Chinchillas we find the Lagotis, the Viscacha, and the
Ctenomys. Then come the Porcupine family, the family of Ground Hogs,
Guinea Pigs and the Agoutis. The Beavers and the extensive Squirrel
family are then followed by the Marmots and Woodchucks, the Prairie
Dogs, and the large family of Hares and Rabbits.