Teething
As mules seldom change hands to any great extent until two or three
years old, it is not deemed necessary here to say any thing of their age
until they have reached two years, so as to give the inexperienced a
wider scope. The mule's mouth undergoes exactly the same changes as the
horse's. Between the ages of two and three these changes begin to take
place in the mule's mouth. The front incisor teeth, two above and two
below, are replaced by the horse for permanent teeth. These teeth are
larger than the others, have two grooves in the outer converse surface,
and the mark is long, narrow, deep, and black. Not having attained their
full growth, they are somewhat lower than the others, the mark in the
two next nippers being nearly worn out, and is also wearing away in the
corner nippers.
A mule at three years old ought to have the central permanent nippers
growing, the other two pairs uniting, six grinders in each jaw, above
and below, the first and fifth level with the others, and the sixth
protruding. As the permanent nippers wear and continue to grow, a narrow
portion of the cone-shaped tooth is exposed to the attrition; and they
look as if they had been compressed. This is not so, however; the mark
of some gradually disappears as the pit is worn away. At the age of
three and a half or four years the next pair of nippers will be changed,
and the mouth at that time cannot be mistaken. The central nippers will
have nearly attained their full growth, and a vacuity will be left where
the second stood; or, they will begin to peep above the gum, and the
corner ones will be diminished in breadth and worn down, the mark
becoming small and faint. At this period also the second pair of
grinders will be shed. At four years the central nippers will be fully
developed, the sharp edges somewhat worn off, and the marks shorter,
wider, and fainter. The next pair will be up, but they will be small,
with the mark deep and extending quite across. Their corner nippers will
be larger than the inside ones, yet smaller than they were, and flat,
and nearly worn out. The sixth grinder will have risen to a level with
the others; and the tushes will begin to appear in the male animal. The
female seldom has them, although the germ is always present in the jaw.
At four years and a half, or between that and five, the last important
change takes place in the mouth of the mule. The corner nippers are
shed, and the permanent ones begin to appear. When the central nippers
are considerably worn, and the next pair are showing marks of wear, the
tush will have protruded, and will generally be a full half inch in
height. Externally it has a rounded prominence, with a groove on either
side, and is evidently hollow within. At six years old the mark on the
central nippers is worn out. There will, however, still be a difference
of color in the center of the tooth. The cement filling up the hole made
by the dipping in of the enamel, will present a browner hue than the
other part of the tooth. It will be surrounded by an edge of enamel, and
there will remain a little depression in the center, and also a
depression around the case of the enamel. But the deep hole in the
center of the enamel, with the blackened surface it presents, and the
elevated edge of the enamel, will have disappeared. The mule may now be
said to have a perfect mouth, all the teeth being produced and fully
grown.
What I have said above must not be taken as a positive guide in all
cases, for mules' mouths are frequently torn, twisted, smashed, and
knocked into all kinds of shapes by cruel treatment, and the
inexperience, to use no harsher term, of those who have charge of them.
Indeed, I have known cases of cruelty so severe that it were impossible
to tell the age of the animal from his teeth.
At seven years old the mark, in the way in which I have described it, is
worn out in the four central nippers, and is also fast wearing away in
the corner teeth. I refer now to a natural mouth that has not been
subjected to injuries. At eight years old the mark is gone from all the
bottom nippers, and may be said to be quite out of the mouth. There is
nothing remaining in the bottom nippers by which the age of the mule can
be positively ascertained. The tushes are a poor guide at any time in
the life of the animal to ascertain his age by; they, more than any
other of the teeth, being most exposed to the injuries I have referred
to. From this time forward, the changes that take place in the teeth may
be of some assistance in forming an opinion; but there are no marks in
the teeth by which a year, more or less, can be positively ascertained.
You can ascertain almost as much from the general appearance of the
animal as from an examination of the mouth. The mule, if he be
long-lived, has the same effect in changing his general appearance from
youth to old age as is shown on the rest of the animal creation.