that they cannot help rapidly scratching the air or the ground in a
useless and ludicrous manner. The terrier just alluded to, when thus
scratched with a stick, will sometimes show her delight by another
habitual movement, namely, by licking the air as if it were my hand.
Horses scratch themselves by nibbling those parts of their bodies which
they can reach with their teeth; but more commonly one horse shows
another where he wants to be scratched, and they then nibble each
other. A friend whose attention I had called to the subject, observed
that when he rubbed his horse s neck, the animal protruded his head,
uncovered his teeth, and moved his jaws, exactly as if nibbling another
horse s neck, for he could never have nibbled his own neck. If a horse
is much tickled, as when curry-combed, his wish to bite something
becomes so intolerably strong, that he will clatter his teeth together,
and though not vicious, bite his groom. At the same time from habit he
closely depresses his ears, so as to protect them from being bitten, as
if he were fighting with another horse.
A horse when eager to start on a journey makes the nearest approach
which he can to the habitual movement of progression by pawing the
ground. Now when horses in their stalls are about to be fed and are
eager for their corn, they paw the pavement or the straw. Two of my
horses thus behave when they see or hear the corn given to their
neighbours. But here we have what may almost be called a true
expression, as pawing the ground is universally recognized as a sign of
eagerness.
Cats cover up their excrements of both kinds with earth; and my
grandfather[116] saw a kitten scraping ashes over a spoonful of pure
water spilt on the hearth; so that here an habitual or instinctive
action was falsely excited, not by a previous act or by odour, but by
eyesight. It is well known that cats dislike wetting their feet, owing,
it is probable, to their having aboriginally inhabited the dry country
of Egypt; and when they wet their feet they shake them violently. My
daughter poured some water into a glass close to the head of a kitten;
and it immediately shook its feet in the usual manner; so that here we
have an habitual movement falsely excited by an associated sound
instead of by the sense of touch.
Kittens, puppies, young pigs and probably many other young animals,
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