HABITS AND HAIR OF CARNIVORES.
Dogs.
Among the canidæ one is able to select a type with whose habits of
life we are more familiar than any other, Canis Familiaris, as he is
affectionately called, the companion of man his master, and faithful
guardian--often unto death. Professor Scott Elliott gives reason to
think that the dog was the first animal tamed by man, and that he was
descended from some wild jackal-like form, probably crossed by the
wolf. The dog is then aptly called by Huxley, the brother of the wolf,
who has been changed by the intelligence of man into the guardian of
the flock. It seems that in his rudimentary stage of domestication he
was an unofficial scavenger among the habitations of neolithic man,
as the pariah is in the East to-day, and that little acts of kindness
towards his offspring on the part of those early men and women were
the first dawnings of a friendship of thousands of years. It is a long
story from the slinking jackal to the bloodhound, mastiff, St. Bernard,
staghound, collie and terrier of to-day, and one which reflects much
credit on both parties to this friendship, just as do those other
long friendships between servant and master, of which we still see
a few examples. Living with us as he does the dog and his habits
of life are an open book: he is then all the better for my humble
purpose here. I would refer again to the curious use of the gender
which we unconsciously apply to the dog. It is no longer “she,” but
“he.” When a dog is looking a little unfriendly how we always try to
wheedle him with “Poor old fellow,” and so on, as a matter of course,
assuming his masculine character. James Payn pointed out once a little
point which proves how good a comrade we have in the dog, when he
reminds us of the cautious approach we usually make to a cat, and the
“hail-fellow-well-met” tone we adopt towards the dog, rolling him over
and using kindly opprobrious terms, such as friends among schoolboys
hurl at one another when they are on the best of terms. A fox-terrier
is, perhaps, the most human of all the numerous types evolved through
the skill of man, and it is a smooth-coated specimen of this variety
which I will examine now as to what his hairy coat can tell us of his
habits.
Some of the Dog’s Habits.
His attitudes which bear on this question are all of the passive order.
His locomotion is so fitful and different from that of the horse that
we shall find on his coat no animal pedometers.
[Illustration: Fig. 38.--Gluteal region of dog, showing whorls over the
tuberosities of the ischia.]
His passive attitudes consist of standing, sitting and lying. He stands
little, sits more, and lies for a great part of each day. The standing
habit has, of course, no influence upon his hair. In sitting he rests
the chief weight of his body on the rounded, bursa-covered surfaces of
his tuberosities of the ischium, in which there is nothing peculiar to
himself. His fore legs are planted nearly upright on the ground and his
hind legs doubled under him or projecting slightly to one or other
side, as we saw in the case of the cow. The fore legs are obviously
in no way affected as to the direction of the hair in the sitting
posture, and the hind legs, being doubled up and subject to the direct
downward weight of the body, are also free from the _sliding pressure_,
which we shall see affects the fore limb when the dog lies prone. Thus
of the three supports, fore legs, hind legs and tuberosities of the
ischium, two are necessarily unaffected in their patterns of hair. The
anatomical conditions of his tuberosities are very different in this
respect. They are covered with a large slippery bursa just beneath
the thick skin, and the slightest movement of this alert and restless
animal, even of his head, conveys to this region a small change of
position. He is virtually like a sick person on a water or air cushion,
and we all know how very small movements of the body are felt in a
slight stirring of the supported parts by these. The effect of this
is that the hair over these bursæ is seldom at rest from external or
extraneous forces, to say nothing of its own imperious constant growth
of one inch in two months. In Fig. 38 one sees the hair-stream curving
round the buttocks towards the region of these bursæ, and trying to
reach the middle line. It meets with so much opposition that the very
conditions for producing a reversed area are present and the result is
just what one would expect to find. The pattern is formed exactly over
the bursæ limited to this area, and it does not expand anywhere because
there is no need for it to do so. So when one observes on the surface
just below the tail a pattern, often in a black-and-tan terrier marked
by a tan patch of hair, one reads the record of the long time spent by
the dog in sitting as he meditates on some fresh or past escapade of “A
Dog’s Day.”
The statement just made that the hind leg does not share in the effects
of pressure is not strictly correct; it applies to the _leg_ properly
so called. But the upper part of the thigh exhibits a very clear
reversal of hair due to the weight of the body acting here against the
streams from the side of the thigh, which are seen endeavouring to make
their way to the inner side. They are arrested by a long ridge of hair
which marks the obstacle presented by the weight of the body acting
here. This completes the story of the way in which sitting affects the
hair of the dog, and is shown in Fig. 38.
Lying Attitude.
[Illustration: Fig. 39.--Foreleg of domestic dog, showing reversed hair
on under surface, which rests on the ground in lying posture.]
[Illustration: Fig. 40.--Showing chest of domestic dog, with reversed
area of hair on each side.]
There are four attitudes adopted by the dog in lying. In the first,
when he sleeps he lies stretched out on his side on some surface, with
his limbs projected nearly straight out, and in the second, he curls
himself up in _his_ armchair in a cosy, rounded posture. But in both
these attitudes there is no such sliding pressure as will affect in
any way the direction of his hair. In two other favourite attitudes
it is far otherwise. When he lies prone he plants his fore limbs out
before his chest and either raises his head to the level of his trunk
or rests it on his fore paws. Each of these attitudes contributes to
a very well-marked change of the hair on the under surface of his fore
arms, to use a convenient human term, one which carries us back to the
story of man and the apes when their fore arms were discussed. On this
surface, from the mechanical conditions involved, a new force, that of
_sliding pressure_, comes into play. The skin here is very loose, as
indeed it is in the greater part of his body, which may almost be said
to form one large subcutaneous bursa. The weight of the fore part of
his body and head acts _downwards and forwards_, and thus opposes the
normal or downward course of the hair on the limb, such as one sees on
the upper surface of his fore arm. The resultant of these two forces
has the effect of acting against the normal slope, and a reversed
direction of the hair is produced very much like that which is seen
in many monkeys and in a small area in man. This is shown in Fig. 39,
which appeared in the small book[54], to which reference has been made,
and it is confined to the part of the limb where the sliding pressure
is seen to act. In this feature again there is a record of his resting
habits, and, of course, the time he spends in the fourth attitude with
his chin resting on his fore paws contributes its share, the mechanical
conditions being similar.
[54] _Use-Inheritance._
This fourth attitude brings in another force of its own towards the
“make-up” of the dog’s patterns of hair. When lying with his head
supported on his paws the lower part of his chest is closely applied to
the upper or flexor surface of the fore legs, and the long-continued
pressure of the latter against the downward or normal streams of hair
on the chest leads to its slope being reversed. This is shown in two
wide patterns of the whorl, feathering and crest, Fig. 40, resembling
closely the corresponding patterns on the chest of a horse. I had
the opportunity many years ago of examining in the Capitol Museum at
Rome two fine sculptures of Molossian hounds, when these matters of
hair-arrangement were occupying my attention, and was much struck with
the fidelity with which the ancient sculptor reproduced such small
facts as the reversed areas of hair in a dog. Phiz himself was not
more true to Nature in his delineation of the projecting hairs on the
human eyebrows. It should be added that the reversed hair in question
occupies only that part of the chest which is in contact with the fore
limb. If one cannot reckon any animal pedometers, to the credit of the
domestic dog I think one may fairly and metaphorically say that his
hairy coat gives an accurate mould of his habits.