modifying the breed.

"Even without any change in the proportional numbers of the animals on
which our wolf preyed, a cub might be born with an innate tendency to
pursue certain kinds of prey. Nor can this be thought very improbable; for
we often observe great differences in the natural tendencies of our
domestic animals: one cat, for instance, taking to catching rats, another
mice; one cat, according to Mr. St. John, bringing home winged game,
another hares or rabbits, and another hunting on marshy ground!, and almost
nightly catching woodcocks or snipes. The tendency to catch rats rather
than mice is known to be inherited. Now, if any slight innate change of
habit or of structure benefited an individual wolf, it would have the best
chance of surviving and of leaving offspring. Some of its young would
probably inherit the same habits or structure, and by the repetition of
this process a new variety might be formed which would either supplant or
coexist with the parent-form of wolf. Or, again, the wolves inhabiting a
mountainous district, and those frequenting the lowlands, would naturally
be forced to hunt different prey; and from a continued preservation of the
individuals best fitted for the two sites, two varieties might slowly be
formed. These varieties would cross and blend where they met; but to this
subject of intercrossing we shall soon have to return. I may add that,
according to Mr. Pierce, there are two varieties of the wolf inhabiting the
Catskill Mountains in the United States, one with a light greyhound-like
form, which pursues deer, and the other more bulky, with shorter legs,
which more frequently attacks the shepherd's flock."--(pp. 90, 91.)


We eke out the illustration here with a counterpart instance, viz., the
remark of Dr. Bachman that "the deer that reside permanently in the swamps
of Carolina are taller and longer-legged than those in the higher grounds."