PARENTAL AND EARLY INSTINCTS.
Under this heading I have put together several notes from my journals on
subjects which have no connection with each other, except that they
relate chiefly to the parental instincts of some animals I have
observed, and to the instincts of the young at a very early period of
life.
While taking bats one day in December, I captured a female of our common
Buenos Ayrean species (Molossus bonariensis), with her two young
attached to her, so large that it seemed incredible she should be able
to fly and take insects with such a weight to drag her down. The young
were about a third less in size than the mother, so that she had to
carry a weight greatly exceeding that of her own body. They were
fastened to her breast and belly, one on each side, as when first born;
and, possibly, the young bat does not change its position, or move, like
the young developed opossum, to other parts of the body, until mature
enough to begin an independent life. On forcibly separating them from
their parent, I found that they were not yet able to fly, but when set
free fluttered feebly to the ground. This bat certainly appeared more
burdened with its young than any animal I had ever observed. I have seen
an old female opossum (Didelphys azarae) with eleven young, large as old
rats--the mother being less than a cat in size--all clinging to various
parts of her body; yet able to climb swiftly and with the greatest
agility in the higher branches of a tree. The actual weight was in this
case relatively much greater than in that of the female bat: but then
the opossum never quitted its hold on the tree, and it also supplemented
its hand-like feet, furnished with crooked claws, with its teeth and
long prehensile tail. The poor bat had to seek its living in the empty
air, pursuing its prey with the swiftness of a swallow, and it seemed
wonderful to me that she should have been able to carry about that great
burden with her one pair of wings, and withal to be active enough to
supply herself and her young with food.
In the end I released her, and saw her fly away and disappear among the
trees, after which I put back the two young bats in the place I had
taken them from, among the thick-clustering foliage of a small acacia
tree. When set free they began to work their way upwards through the
leaves and slender twigs in the most adroit manner, catching a twig with
their teeth, then embracing a whole cluster of leaves with their wings,
just as a person would take up a quantity of loose clothes and hold them
tight by pressing them against the chest. The body would then emerge
above the clasped leaves, and a higher twig would be caught by the
teeth; and so on successively, until they had got as high as they
wished, when they proceeded to hook themselves to a twig and assume the
inverted position side by side; after which, one drew in its head and
went to sleep, while the other began licking the end of its wing, where
my finger and thumb had pressed the delicate membrane. Later in the day
I attempted to feed them with small insects, but they rejected my
friendly attentions in the most unmistakable manner, snapping viciously
at me every time I approached them. In the evening, I stationed myself
close to the tree, and presently had the satisfaction of seeing the
mother return, flying straight to the spot where I had taken her, and in
a few moments she was away again and over the trees with her twins.
Assuming that these two young bats had, before I found them, existed
like parasites clinging to the parent, their adroit actions when
liberated, and their angry demonstrations at my approach, were very
astonishing; for in all other mammals born in a perfectly helpless
state, like rodents, weasels, edentates, and even marsupials, the
instincts of self-preservation are gradually developed after the period
of activity begins, when the mother leads them out, and they play with
her and Avith each other. In the bat the instincts must ripen to
perfection without exercise or training, and while the animal exists as
passively as a fruit on its stem.
I have observed that the helpless young of some of the mammals I have
just mentioned seem at first to have no instinctive understanding of the
language of alarm and fear in the parent, as all young-birds have, even
before their eyes are open. Nor is it necessary that they should have
such an instinct, since, in most cases, they are well concealed in
kennels or other safe places; but when, through some accident, they are
exposed, the want of such an instinct makes the task of protecting them
doubly hard for the parent. I once surprised a weasel (Galictis barbara)
in the act of removing her young, or conducting them, rather; and when
she was forced to quit them, although still keeping close by, and
uttering the most piercing cries of anger and solicitude, the young
continued piteously crying out in their shrill voices and moving about
in circles, without making the slightest attempt to escape, or to
conceal themselves, as young birds do.
Some field mice breed on the surface of the ground in ill-constructed
nests, and their young are certainly the most helpless things in nature.
It is possible that where this dangerous habit exists, the parent has
some admirable complex instincts to safeguard her young, in addition to
the ordinary instincts of most animals of this kind. This idea was
suggested to me by the action of a female mouse which I witnessed by
chance. While walking in a field of stubble one day in autumn, near
Buenos Ayres, I suddenly heard, issuing from near my feet, a chorus of
shrill squealing voices--the familiar excessively sharp little needles
of sound emitted by young, blind and naked mice, when they are disturbed
or in pain. Looking down, I saw close to my foot a nest of them--there
were nine in all, wriggling about and squealing; for the parent,
frightened at my step, had just sprung from them, overturning in her
hurry to escape the slight loosely-felted dome of fine grass and
thistledown which had covered them. I saw her running away, but after
going six or seven yards she stopped, and, turning partly round so as to
watch me, waited in fear and trembling. I remained perfectly
motionless--a sure way to allay fear and suspicion in any wild
creature,--and in a few moments she returned, but with the utmost
caution, frequently pausing to start and tremble, and masking her
approach with corn stumps and little inequalities in the surface of the
ground, until, reaching the nest, she took one of the young in her
mouth, and ran rapidly away to a distance of eight or nine yards and
concealed it in a tuft of dry grass.
Leaving it, she returned a second time, in the same cautious manner, and
taking another, ran with it to the same spot, and concealed it along
with the first. It was curious that the first young mouse had continued
squealing after being hidden by the mother, for I could hear it
distinctly, the air being very still, but when the second mouse had been
placed with it, the squealing ceased. A third time the old mouse came,
and then instead of going to the same spot, as I had expected, she ran
off in an opposite direction and disappeared among the dry weeds; a
fourth was carried to the same place as the third; and in this way they
were all removed to a distance of some yards from the nest, and placed
in couples, until the last and odd one remained. In due time she came
for it, and ran away with it in a new direction, and was soon out of
sight; and although I waited fully ten minutes, she did not return; nor
could I afterwards find any of the young mice when I looked for them, or
even hear them squeal.
I have frequently observed newly-born lambs on the pampas, and have
never failed to be surprised at the extreme imbecility they display in
their actions; although this may be due partly to inherited degeneracy
caused by domestication. This imbecile condition continues for two,
sometimes for three days, during which time the lamb apparently acts
purely from instincts, which are far from perfect; but after that,
experience and its dam teach it a better way. When born its first
impulse is to struggle up on to its feet; its second to suck, but here
it does not discriminate like the newly-hatched bird that picks up its
proper food, or it does not know what to suck. It will take into its
mouth whatever comes near, in most cases a tuft of wool on its dam's
neck; and at this it will continue sucking for an indefinite time. It is
highly probable that the strong-smelling secretion of the sheep's udder
attracts the lamb at length to that part; and that without something of
the kind to guide it, in many cases it would actually starve without
finding the teats. I have often seen lambs many hours after birth still
confining their attention to the most accessible locks of wool on the
neck or fore legs of the dams, and believe that in such cases the long
time it took them to find the source of nourishment arose from a
defective sense of smell. Its next important instinct, which comes into
play from the moment it can stand on its feet, impels it to follow after
any object receding from it, and, on the other hand, to run from
anything approaching it. If the dam turns round and approaches it from
even a very short distance, it will start back and run from her in fear,
and will not understand her voice when she bleats to it: at the same
time it will confidently follow after a man, dog, horse, or any other
animal moving from it. A very common experience on the pampas, in the
sheep-country, is to see a lamb start up from sleep and follow the
rider, running along close to the heels of the horse. This is
distressing to a merciful man, tor he cannot shake the little simpleton
off, and if he rides on, no matter how fast, it will keep up him, or
keep him in sight, for half a mile or a mile, and never recover its dam.
The gaucho, who is not merciful, frequently saves himself all trouble
and delay by knocking it senseless with a blow of his whip-handle, and
without checking his horse. I have seen a lamb, about two days old,
start up from sleep, and immediately start off in pursuit of a puff ball
about as big as a man's head, carried past it over the smooth turf by
the wind, and chase it for a distance of five hundred yards, until the
dry ball was brought to a stop by a tuft of coarse grass. This
blundering instiuct is quickly laid aside when the lamb has learned to
distinguish its dam from other objects, and its dam's voice from other
sounds. When four or five days old it will start from sleep, but instead
of rushing blindly away after any receding object, it first looks about
it, and will then recognize and run to its dam.
I have often been struck with the superiority of the pampa or
creolla--the old native breed of sheep--in the greater vigour of the
young when born over the improved European varieties. The pampa descends
to us from the first sheep introduced into La Plata about three
centuries ago, and is a tall, gaunt bony animal, with lean dry flesh,
like venison, and long straight wool, like goats' hair. In their
struggle for existence in a country subject to sudden great changes of
temperature, to drought, and failure of grass, they have in a great
measure lost the qualities which make the sheep valuable to man as a
food and wool-producing animal; but on the other hand they have to some
extent recovered the vigour of a wild animal, being hardy enough to
exist without any shelter, and requiring from their master man only
protection from the larger carnivores. They are keen-scented, swift of
foot and Wonderfully active, and thrive where other breeds would quickly
starve. I have often seen a lamb dropped on the frosty ground in
bitterly cold windy weather in midwinter, and in less than five seconds
struggle to its feet, and seem as vigorous as any day-old lamb of other
breeds. The dam, impatient at the short delay, and not waiting to give
it suck, has then started off at a brisk trot after the flock, scattered
and galloping before the wind like huanacos rather than sheep, with the
lamb, scarcely a minute in the world, running freely at her side.
Notwithstanding its great vigour it has been proved that the pampa sheep
has not so far outgrown the domestic taint as to be able to maintain its
own existence when left entirely to itself. During the first half of
this century, when cattle-breeding began to be profitable, and wool was
not worth the trouble of shearing, and the gaucho workman would not eat
mutton when beef was to be had, some of the estancieros on the southern
pampas determined to get rid of their sheep, which were of no value to
them; and many flocks were driven a distance out and lost in the wilds.
Out of many thousands thus turned loose to shift for themselves, not one
pair survived to propagate a new race of feral sheep; in a short time
pumas, wild dogs, and other beasts of prey, had destroyed them all. The
sterling qualities of the pampa sheep had their value in other times; at
present the improved kinds are alone considered worth having, and the
original sheep of the country is now rapidly disappearing, though still
found in remote and poor districts, especially in the province of
Cordova; and probably before long it will become extinct, together with
the curious pug-nosed cow of the pampas.
I have had frequent opportunities of observing the young, from one to
three days old, of the Cervus campestris--the common deer of the pampas,
and the perfection of its instincts at that tender age seem very
wonderful in a ruminant. When the doe with, fawn is approached by a
horseman, even when accompanied with dogs, she stands perfectly
motionless, gazing fixedly at the enemy, the fawn motionless at her
side; and suddenly, as if at a preconcerted signal, the fawn rushes
directly away from her at its utmost speed; and going to a distance of
six hundred to a thousand yards conceals itself in a hollow in the
ground or among the long grass, lying down very close with neck
stretched out horizontally, and will thus remain until sought by the
dam. When very young if found in its hiding-place it will allow itself
to be taken, making no further effort to escape. After the fawn has run
away the doe still maintains her statuesque attitude, as if resolved to
await the onset, and only when the dogs are close to her she also rushes
away, but invariably in a direction as nearly opposite to that taken by
the fawn as possible. At first she runs slowly, with a limping gait, and
frequently pausing, as if to entice her enemies on, like a partridge,
duck or plover when driven from its young; but as they begin to press
her more closely her speed increases, becoming greater the further she
succeeds in leading them from the starting-point.
The alarm-cry of this deer is a peculiar whistling bark, a low but
far-reaching sound; but when approaching a doe with young I have never
been able to hear it, nor have I seen any movement on the part of the
doe. Yet it is clear that in some mysterious way she inspires the fawn
with sudden violent fear; while the fawn, on its side, instead of being
affected like the young in other mammals, and sticking closer to its
mother, acts in a contrary way, and runs from her.
Of the birds I am acquainted with, the beautiful jacana (Parra jacana)
appears to come into the world with its faculties and powers in the most
advanced state. It is, in fact, ready to begin active life from the very
moment of leaving the shell, as I once accidentally observed. I found a
nest on a small mound of earth in a shallow lagoon, containing four
eggs, with the shells already chipped by the birds in them. Two yards
from the small nest mound there was a second mound covered with coarse
grass. I got off my horse to examine the nest, and the old birds,
excited beyond measure, fluttered round me close by pouring out their
shrill rapidly-reiterated cries in an unbroken stream, sounding very
much like a policeman's rattle. While I was looking closely at one of
the eggs lying on the palm of my hand, all at once the cracked shell
parted, and at the same moment the young bird leaped from my hand and
fell into the water. I am quite sure that the young bird's sudden escape
from the shell and my hand was the result of a violent effort on its
part to free itself; and it was doubtless inspired to make the effort by
the loud persistent screaming of the parent birds, which it heard while
in the shell. Stooping to pick it up to save it from perishing, I soon
saw that my assistance was not required, for immediately on dropping
into the water, it put out its neck, and with the body nearly submerged,
like a wounded duck trying to escape observation, it swam rapidly to the
second small mound I have mentioned, and, escaping from the water,
concealed itself in the grass, lying close and perfectly motionless like
a young plover.
In the case of the pampa or creolla sheep, I have shown that during its
long, rough life in La Plata, this variety has in some measure recovered
the natural vigour and ability to maintain existence in adverse
circumstances of its wild ancestors. As much can be said of the creolla
fowl of the pampas; and some observations of mine on the habits of this
variety will perhaps serve to throw light on a vexed question of Natural
History--namely, the cackling of the hen after laying, an instinct which
has been described as "useless" and "disadvantageous." In fowls that
live unconfined, and which are allowed to lay where they like, the
instinct, as we know it, is certainly detrimental, since egg-eating dogs
and pigs soon learn the cause of the outcry, and acquire a habit of
rushing off to find the egg when they hear it. The question then arises:
Does the wild jungle fowl possess the same pernicious instinct?
The creolla is no doubt the descendant of the fowl originally introduced
about three centuries ago by the first colonists in La Plata, and has
probably not only been uncrossed with any other improved variety, such
as are now fast taking its place, and has lived a much freer life than
is usual with the fowl in Europe. It is a rather small, lean, extremely
active bird, lays about a dozen eggs, and hatches them all, and is of a
yellowish red colour--a hue which is common, I believe, in the old
barn-door fowl of England. The creolla fowl is strong on the wing, and
much more carnivorous and rapacious in habits than other breeds; mice,
frogs, and small snakes are eagerly hunted and devoured by it. At my
home on the pampas a number of these fowls were kept, and were allowed
to range freely about the plantation, which was large, and the adjacent
grounds, where there were thickets of giant cardoon thistle, red-weed,
thorn apple, &c. They always nested at a distance from the house, and it
was almost impossible ever to find their eggs, on account of the extreme
circumspection they observed in going to and from their nests; and when
they succeeded in escaping foxes, skunks, weasels, and opossums, which,
strange to say, they often did, they would rear their chickens away out
of sight and hearing of the house, and only bring them home when winter
deprived them of their leafy covering and made food scarce. During the
summer, in my rambles about the plantation, T would occasionally
surprise one of these half-wild hens with her brood; her distracted
screams and motions would then cause her chicks to scatter and vanish in
all directions, and, until the supposed danger was past, they would lie
as close and well-concealed as young partridges. These fowls in summer
always lived in small parties, each party composed of one cock and as
many hens as he could collect--usually three or four. Each family
occupied its own feeding ground, where it would pass a greater portion
of each day. The hen would nest at a considerable distance from the
feeding ground, sometimes as far as four or five hundred yards away.
After laying an egg she would quit the nest, not walking from it as
other fowls do, but flying, the flight extending to a distance of from
fifteen to about fifty yards; after which, still keeping silence, she
would walk or run, until, arrived at the feeding ground, she would begin
to cackle. At once the cock, if within hearing, would utter a responsive
cackle, whereupon she would run to him and cackle no more. Frequently
the cackling call-note would not be uttered more than two or three
times, sometimes only once, and in a much lower tone than in fowls of
other breeds.
If we may assume that these fowls, in their long, semi-independent
existence in La Plata, have reverted to the original instincts of the
wild Gallus bankiva, we can see here how advantageous the cackling
instinct must be in enabling the hen in dense tropical jungles to rejoin
the flock after laying an egg. If there are egg-eating animals in the
jungle intelligent enough to discover the meaning of such a short,
subdued cackling call, they would still be unable to find the nest by
going back on the bird's scent, since she flies from the nest in the
first place; and the wild bird probably flies further than the creolla
hen of La Plata. The clamorous cackling of our fowls would appear then
to be nothing more than a perversion of a very useful instinct.