TORTOISES, TURTLES, AND LIZARDS
We now come to the cold-blooded animals, which are divided into three
classes. First we have the reptiles, whose hearts are formed of three
chambers, and which breathe air by means of lungs. Next come the
amphibians, which are like the reptiles in many ways, but which have to
pass through a tadpole stage before they reach the perfect form. And,
thirdly, there are the fishes, whose hearts are divided into two
chambers only, and which breathe water by means of gills.
TORTOISES AND TURTLES
At the head of the reptiles stand the tortoises and turtles, whose
bodies are shut up in a kind of horny box, which we generally call the
shell. In reality, however, it is not a shell at all; for the upper
part, which we call the carapace, is a development of the spine and the
ribs, while the lower part, which is known as the plastron, is a
development of the breast-bone. These animals, in fact, have part of
their skeletons inside their bodies and part outside; so that they are
really shut up in their own bones!
The so-called shell of a tortoise or a turtle is always very hard and
strong, so that you can stand upon quite a small tortoise without
hurting it in the least and in most cases the head and legs can be
tucked away inside it, so that the animal is safely protected from
almost every foe.
None of the turtles and tortoises have any teeth. But the edges of their
jaws are so sharp and horny that they can often inflict a very severe
bite. Some of the larger turtles, indeed, could snap off the fingers of
a man's hand as easily as you could bite through a carrot!
[Illustration: TYPES OF WATER-BIRDS
1. Mandarin Duck. 2. Penguin. 3. Heron. 4. Pelican.
5. Bittern. 6. Flamingo. 7. Crane.]
LAND-TORTOISES
The most famous of all the tortoises is the common land-tortoise, or
Greek tortoise, which is found in many parts of the south of Europe, and
also in Asia Minor. This is the animal which is so often kept as a pet,
and about which so much pleasant literary interest has gathered. It does
not grow to any great size, but will live in a garden for many years,
crawling about by night as well as by day. Early in the autumn it buries
itself underground, and falls into a deep sleep, from which it does not
awake until the spring.
This tortoise is a vegetable-feeder, and is very fond of lettuce leaves,
more especially when they are quite crisp and fresh, so that it can
easily nip them to pieces with its sharp jaws. If they are rather old
and stringy, it will hold them down with its front feet while it tears
them asunder. And if you keep one of these animals as a pet, and want to
give it a great treat, there is nothing that it likes better than a
little milk. It is amusing to see how it drinks, for it first scoops up
a little milk in its lower jaw, just as if it were using a spoon, and
then holds up its head in order that the liquid may trickle down its
throat.
There are a good many other kinds of land-tortoises, some of which grow
to a very great size. The largest of all comes from the Galapagos
Islands, and is quite a giant; for some of them are more than four feet
long, and weigh between eight and nine hundred pounds! These huge
creatures, however, are now nearly extinct.
TURTLES
The turtles are distinguished from the tortoises by the structure of
their feet, which are flattened out in such a way as to serve as paddles
in the water. For this reason these reptiles hardly ever come upon land
except when they want to lay their eggs; and they can swim so
well that they are often met with many hundreds of miles out at sea.
One of the best known of these creatures is the hawksbill turtle, which
is so called because its mouth is shaped just like the beak of a hawk.
The carapace is made up of thirteen large scales, which overlap one
another for about a third of their length, just like the slates on the
roof of a house.
These scales are very valuable, for the best tortoise-shell is obtained
from them. When they are first taken from the animal they do not look
like tortoise-shell at all, for they are dull and crumpled and brittle.
But after they have been boiled, and steamed, and pressed for some hours
they quite change their character, and become so soft that they can
easily be molded into any required shape.
The eggs of this turtle are laid in a hole which the mother scrapes in
the sand, and are hatched by the heat of the sun. As soon as the little
turtles make their appearance they hurry off as fast as they can toward
the water. But they are very good to eat, and a number of hungry animals
and birds are always on the lookout for them, so that a very great many
are snapped up and devoured before they can plunge into the waves.
The famous turtle soup, which is considered so great a dainty, is made
from the flesh of the green turtle, which is found most plentifully off
the island of Ascension and in the West Indies. It grows to a great
size, for it is often four feet six inches in length and three feet in
breadth, while it may weigh nearly three-quarters of a ton. Of course it
is not at all easy to capture such big creatures. But they are generally
pursued when they come on shore to lay their eggs, and are turned over
on their backs by means of a lever. They are then perfectly helpless,
and can be left lying where they are until a number of others have been
overturned in the same way, when they are lifted into a boat one by one,
and are taken on board ship. There they thrive quite well if a pail of
water is thrown over them two or three times a day, and are generally in
very good condition when they reach this country.
It is said that if one of these turtles has once begun to lay her eggs
in the sand, nothing will induce her to pause in her task until she has
finished it, and that even if the eggs are taken away from her as fast
as she lays them, she will still go steadily on just as if she were
undisturbed.
CROCODILES AND ALLIGATORS
Of course you know what these huge creatures are like. They are just
enormous lizards, fifteen, or twenty, or even thirty feet long, with
very short legs, and very clumsy bodies, and very long tails. And their
great jaws are armed with rows of most terrible teeth.
But what is the difference between crocodiles and alligators? Well, in
some ways they are certainly very much alike; but you can always tell
them by the shape of their heads, for the muzzle of a crocodile is
always narrowed just behind the nostrils, while that of an alligator is
not. And in the crocodiles the fourth lower tooth fits into a notch in
the edge of the upper jaw, so that you can distinctly see it even when
the mouth is closed.
All these creatures live in the water, and spend a great deal of their
time lying motionless on the surface, when they look like floating logs.
One would think that they were fast asleep. But woe betide any animal
which comes to drink from the bank close by, for one of the great
reptiles instantly dives, swims swiftly along under water, and knocks it
into the stream by a blow from its mighty tail.
There is scarcely any animal which does not fall a victim at times to
these giant lizards. And as soon as the unfortunate creature is knocked
into the water it is dragged beneath the surface, and held there until
it is drowned. You would think that the reptiles themselves would be
drowned, wouldn't you, as they have to remain submerged for many minutes
with their jaws widely opened? But they have a very curious valve at the
back of the throat, and as soon as the mouth is opened this closes so
tightly that not even the tiniest drop of water can find its way down
the throat.
Both crocodiles and alligators swim with very great speed by waving
their powerful tails from side to side in the water. They can run, too,
with some little pace upon land. But it is very easy to avoid them, for
the bones of their necks are made in such a way that they cannot turn
their heads, and all that one has to do if pursued is to spring suddenly
to one side. But of course it is necessary to avoid the stroke of the
tail.
The crocodiles always lay their eggs in the sand on the bank of a river.
The eggs are about as big as those of a goose, and are generally buried
at a depth of a couple of feet. The mother reptile always sleeps on the
top of the nest, and it is said that when the little ones are ready to
hatch out they utter a curious little cry. The mother hears this, and
scoops away the sand under which they are buried, in order that they may
have no difficulty in making their escape.
Crocodiles are found in the warmer parts of Africa, Asia, America, and
Australia, and in some of the larger rivers are very plentiful. Just now
and then they venture down into the sea. Alligators, which also are
known as caymans and jacares, are only found in America and place their
eggs in holes dug in the mud or earth beside the water. In the colder
parts of the range they burrow under the mud of the banks and spend the
winter in sleep.
THE LIZARDS
Lizards look at first glance like diminutive alligators, because most of
them have long-jawed heads, short legs wide apart, and long tails; but
really they are near relatives of the snakes, for not only their
internal structure but the coat of scales is snake-like; but an
important difference is that the jaws of the lizard are firmly hinged to
a solid skull, while the bones of the skull of the snake, including
those of the jaws, are connected by elastic cartilages which enable them
to spread apart and permit the swallowing of a mouthful astonishingly
large. But the lizards have no need of such a convenience, for they
subsist almost wholly on insects, or else are vegetable-eaters. Lizards
are almost entirely denizens of the tropics, and seem to rejoice in the
fiercest heat. They will lie contentedly in the desert at noonday on
rocks so hot that they would blister your hand if you touched them.
Therefore few are to be found in Europe or North America, except in the
extreme south.
THE BLINDWORM
Two or three small kinds are to be found in the south of England, one of
which is curious as representing a tribe, largely represented in other
parts of the world, of legless burrowing lizards, which look much like
little snakes, for none of them are more than ten or twelve inches long,
while they are of the thickness of a lead-pencil. They look so shiny and
serpent-like that many people are afraid of them.
But the blindworm, or slowworm, as this creature is called, is perfectly
harmless. It cannot bite you, for its teeth are far too tiny to pierce
the skin; and it cannot sting you, because it has no sting. There is its
odd little forked tongue, of course, which is always darting in and out
of its mouth, just like that of a snake. But this tongue is only a
feeler. Whenever a blindworm comes to an object it does not quite
understand, it touches it gently all over with the tip of its tongue,
just as we might touch it with the tips of our fingers.
Notwithstanding its name, the blindworm has a pair of very good, though
rather small, beady black eyes; and, of course, it is not a worm.
During the daytime the blindworm mostly lies hidden under a large stone;
and on turning such a stone over, one may sometimes find two or three of
these lizards all coiled up together. But in the evening they leave
their hiding-places, and go out to search for the tiny white slugs on
which they feed.
When it is suddenly startled the blindworm sometimes behaves in a very
odd way. It stiffens its body, gives a kind of shudder and a twist, and
actually snaps off its own tail! Then the tail begins to writhe about on
the ground, wriggling and curling and even leaping up into the air in
the most curious manner; and while you are watching its antics, the
blindworm creeps away into some place of safety. You would think that it
must suffer a great deal of pain from this extraordinary injury,
wouldn't you, and that the blindworm would feel it quite as much as a
man would feel if his leg were cut off? But it does not seem to suffer
at all; and stranger still, a new tail very soon begins to grow
in the place of the old one, so that in the course of a very few weeks
the lizard is just as perfect as it was before!
SKINKS
These are queer little lizards with four short legs and very stumpy
tails, which are found in many parts of Africa and Asia. They live in
sandy deserts, and are rather slow in their movements as a rule. But if
a fly should settle anywhere near them they will dart upon it with the
most surprising quickness, and will hardly ever fail to capture it. And
if they are alarmed they will burrow into the sand so rapidly that they
really seem to sink into it just as if it were water. In a very few
seconds, indeed, they will bury themselves to a depth of at least two or
three feet.
In olden days skinks were very much used in medicine, and the powder
obtained from their dried bodies was thought to be a certain cure for
many diseases! It does not seem a very nice idea, yet even to this day
skinks are used for the same purpose in Eastern countries.
There are several different kinds of these curious lizards, of which the
common skink, found in Northern Africa, is the best known. It is about
three inches and a half in length, and is yellowish brown in color, with
a number of darker bands on the sides of the body.
GECKOS
Odder still are the geckos, which have their toes swollen out at the
tips into round sucker-like pads, by means of which they can climb a
wall or a pane of glass with the greatest ease, or even walk about like
flies on the ceiling. They are very fond of getting into houses,
generally remaining hidden in some dark corner during the day, but
coming out toward evening to search for insects, and continually
uttering their curious little cry of "geck-geck-geck-o."
People used to be very much afraid of geckos, some thinking
that they could squirt out poison from the pads of their toes which
would act like the sting of a nettle, and others declaring that their
teeth were so sharp and strong that they could pierce even a sheet of
steel! But the real fact is that these lizards are perfectly harmless,
and cannot injure any living creature except the insects upon which they
feed. When they take up their quarters in a house they soon become
extremely tame, and will even climb up on the dinner-table to be fed.
Geckos are found in almost all hot countries of the Old World, and
nearly three hundred different kinds have been found altogether.
IGUANAS
American lizards are almost wholly members of the numerous iguana
family, which takes its name from the big examples found from Mexico
down into Brazil. The commonly known one when fully grown will measure
four feet from the tip of its blunt, top-shaped head to the end of its
long tapering tail. It looks rather forbidding, for a row of sharp
spikes runs right along its back, while under its chin is a great
dewlap. Yet it is not quite so terrible as it seems, for though it will
bite fiercely if it is driven to bay, and use its long tail like the
lash of a whip, it will always run away if it can, and will either climb
into the topmost boughs of a tree, or plunge into a stream and swim
away.
This reptile is a very good swimmer, driving itself rapidly through the
water by waving its long tail from side to side, just like a crocodile
or an alligator. And it can dive beneath the surface and remain at the
bottom for a very long time without coming up to breathe.
Iguanas live chiefly among the branches of trees which overhang the
water. Their flesh is very good to eat, for it is as tender as the
breast of a young chicken. Their eggs, too, which they bury in the sand
on the river-bank, are often used as food, and it is said that, no
matter how long they may be boiled, they never become hard.
VARIOUS AMERICAN LIZARDS
The hot open plains which stretch from central Texas westward to the
Pacific Ocean, and northward in Utah and Nevada, abound in a great
variety of small lizards, none more than eighteen inches or so in
length. Some are fat and short-tailed, some slender and swift, with
tails like whiplashes. Some have gay colors and the power of changing
them more or less, while others are dull of hue and uninteresting or
repulsive to look at. Mostly they are insect-eaters, but some subsist
upon plants; and one of the latter is the big fat one known in southern
California as the "alderman."
Another strange one is the broad, flat creature so frequently seen all
over the Southwest, and called horned toad, on account of its shape and
habit of sitting on its squat legs, with its tail tucked sideways out of
sight. It is covered almost all over with long and sharp spikes. Those
on its head, which are directed backward, are the longest; and from
these it gets its name of horned toad. But those on the back are very
nearly as long, while there are several rows upon the tail as well. Yet
it is perfectly harmless, for even when it is caught for the first time
it never seems to use either its spikes or its teeth.
But it has another peculiarity which it sometimes uses as a means of
defence, and that is a very strange one indeed. It actually squirts out
little jets of blood from its eyes! That seems impossible, doesn't it?
Yet there is no doubt at all about it, for when these lizards have been
kept in captivity, and have been rather roughly handled, they have been
known to squirt several drops of blood at a time to a distance of twelve
or fifteen inches! Yet nobody seems to know how they do it.
THE GILA MONSTER
This same region, however, contains a poisonous lizard--the only kind of
lizard in the world known to have sacs of venom in the mouth. This venom
enters any wound made by the animal's biting with certain teeth, and
acts upon the animal bitten like snake-poison. This is a
sluggish, round-headed, short-tailed creature which dwells in the sandy
plains along the Mexican boundary, and is called the Gila monster, or,
scientifically, the _Heloderma_. Its scales are rounded, so that
this lizard looks as if dressed in pebbled goatskin; and its colors are
black and yellow, in irregular blotches. The hunters and sheep-herders
are more afraid of it than need be, for it is sleepy and will never use
its poisonous teeth without great provocation, so that it is only
necessary to leave it alone in order to escape any harm.
THE FRILLED LIZARD
This lizard is a native of Australia, and has round its neck a kind of
frill, or ruff, from six to eight inches in diameter! As a rule this
frill is folded round the throat, so that from a little distance one
would scarcely notice it. But as soon as the reptile is excited or
alarmed it spreads it out, sits on its hinder legs and its tail, raises
its head and body, and shows its teeth, just as if it were going to fly
at its enemy. This is only pretence, however, for though the lizard
grows to a length of nearly three feet, it is quite harmless.
Another very curious habit which this lizard has is that of walking
upright on its hind legs, in the attitude of a dog when "begging." It
will even run in this position, and most odd it then looks. It is a
capital climber, and spends most of its life in the trees, to which it
always tries to escape when it thinks itself in danger. In color the
frilled lizard is yellowish brown mottled with black.
THE CHAMELEON
Strangest of all strange lizards, however, is the chameleon. In the
first place, this lizard has a very long tongue, which it can dart out
to a really wonderful distance from its mouth. This tongue looks very
much like a worm, and is exceedingly sticky, so that all that a
chameleon has to do when it sees a fly settling near it is to dart out
its tongue and touch it with the tip. Then the fly adheres to
it, and is carried back into the mouth so quickly that it is almost
impossible to see what becomes of it. In this way it can catch a fly at
a distance of fully six inches.
Then the chameleon has most extraordinary eyes. They are about as big as
peas; but instead of having lids which move up and down, as ours do,
they are entirely covered by the lids with the exception of just a tiny
round space in the middle. The lizard sees, in fact, through a hole in
the middle of its eyelid. That is strange enough; but what is stranger
still is that the animal can move its eyes in different directions at
the same time. They are hardly ever still for a single moment. But
instead of moving together, like those of all other animals, one may be
looking upward toward the sky and the other downward toward the ground;
or the right eye may be peering forward in front of the nose while the
left one is glancing backward toward the tail! Indeed, it would be very
difficult to find an odder sight than that of a chameleon when it is
moving its eyes about. They really look just as if they belonged to two
different animals.
But the most wonderful fact of all about the chameleon is that it can
change its color whenever it chooses.
How it does so no one quite knows. But the very same animal which is
brown all over as it sits upon a branch will become green all over if
you put it among leaves. The last thing at night, probably, you will
find that it is gray. Next day, perhaps, brown spots will appear upon
its body, and pinkish stripes upon its sides. And occasionally it may be
violet, and sometimes yellow, and sometimes nearly black. So that if you
were to go and look at a chameleon, and then go and look at it again
half an hour afterward, you might very likely take it for a wholly
different animal!
Then the chameleon has very odd habits. If it is annoyed, for example,
it puffs out its body in the most extraordinary way till it is nearly
double its ordinary size and its skin is stretched almost as tight as
the parchment of a drum. When it is caught it hisses like a snake. And
really it must be the very laziest creature on earth. If it lifts a foot
into the air it will often wait for quite a minute before it puts it
down again, and for two or even three minutes more before it
takes a second step. Then it always has to rest for some little time
after uncoiling its tail from a branch, while when it coils it round
another it stops and rests again. It will hardly travel two yards, in
fact, in a day.
Chameleons are found in many parts of Africa and Asia, and also in
Southeastern Europe.