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the scales on tho upper surface and sides are small and smooth ; and the prehensile
tail is of moderate length, or short, with the whole or greater part of the. inferior
shields arranged in two rows.

Distribution and Pythons, or, as they are frequently termed, rock-snakes, are
Habits. represented by nine species, and range over tropical and South
Africa, South-Eastern Asia, and Australasia. With the exception of the American
anaconda, some of the pythons are the largest of all snakes, and although there
has been much exaggeration in this respect, it is now ascertained that the
Indian python (Python mobu/rus), represented in the figure on p. 181, occasionally
attains a length of 30 feet, while the West African python (P. scbcv) is stated to
reach 23 feet. It is, however, but seldom that pythons of more than from 15 to 20
feet in length are met with, and these are sufficiently formidable creatures, since
they have a circumference as large as a man's thigh, and easily kill such animals
as small deer, full-grown sheep, and dogs of considerable si/e. They are, however,
unable, according to Dr. Gtinther, to devour animals of larger dimensions than a
half-grown sheep. A python destroys its victim in much the same manner as do
many of the smaller snakes, gradually smothering it by throwing over it coil after
coil of its body. In swallowing, writes Dr. Giinther, pythons "always commence
with the head [as shown in the figure of the African species], and as they live



PYTHONS AND BOAS, 183

entirely on mammals and birds, the hairs and feathers offer a considerable impedi-
ment to the passage down the throat. The process of deglutition is, therefore, slow,
but it would be much slower except for the great quantity of saliva discharged
over the body of the victim. During the time, of digestion, especially when the
prey has been a somewhat large animal, the snake becomes very lazy; it moves
itself slowly when disturbed, or defends itself with little vigour when attacked.




AFRICAN PYTHON SWALLOWING A BIRD (\ nat. size).

At any other time the rock-snakes will fiercely defend themselves when they
perceive that no retreat is left to them. Although individuals kept in captivity
become tamer, the apparent tameness of specimens brought to Europe is much
more a state of torpidity caused by the climate than an actual alteration of their
naturally fierce temper." In their general habits snakes of this genus are
nocturnal, and they generally live on or among trees in the neighbourhood of
water, frequently swimming in the water. The reticulated python (P. reticulatus)
of Burma and the Malayan Archipelago, which attains a length of some 16 feet,



1 84 SNAKES.

not unfrequently takes up its abode in buildings, whence it issues forth at night
to capture such prey as it can find.

It had long bren reported by travellers in India that pythons incubated their
eggs, and although such reports were received with incredulity, their truth was
established in 1841, when an African python in the Jardin des Plantes, Paris, laid
fifteen eggs on the 6th of May, which she subsequently proceeded to incubate.
When first laid, the eggs, which were completely separate, were soft, oval, and
ashy grey, but they soon assumed a rounder form, and a clear white tint, at the
same time hardening. The parent collected them into a cone-shaped pile, around
which she rolled herself in such a manner as to conceal the whole number, with
her head forming the summit of the cone. For upwards of six-and-fifty days this
position was maintained without movement, except when persons attempted to
touch the eggs. On July the 2nd, the shell of one of the eggs split, revealing a
fully-formed python within ; and on the next day the little creature came forth into
the world. During the four succeeding days, eight more snakes made their appear-
ance, but the rest of the eggs were spoilt. In from ten days to a fortnight the
young pythons changed their skins, after which they caught and devoured some
live sparrows, seizing and smothering them in the manner in which full-grown
individuals destroy prey of larger size.

species of According to Mr. Boulenger, the number of species of python is

Python. nine, which may be divided into two groups, according as to whether
the number of pairs of shields on the lower surface of the tail exceeds or falls short
of fifty. The former group may be further subdivided into two sections, according
as to whether the number of scales in a row round the thickest part of the body
varies from thirty-nine to sixty, or from sixty-one to ninety-three. The first-
representative of the former of these subgroups is the Australian diamond-snake
(P. spilotis), represented in the illustration on p. 185, which is characterised by the
crown of the head being covered with scales or small irregular shields, and the
presence of pits on two or three of the upper labial shields of the snout. This
snake, which was formerly referred to a genus apart (Morelia), is an inhabitant of
New Guinea and Australia, and is of comparatively small size, attaining a total
length of only about 6| feet ; its coloration being extremely variable. The variety
in which the skin is most c po' ted was long regarded as a distinct species, under
the name of the carpet-snake. The other two members of this group are the
amethystine python (P. amethystimis) and the Timor python (P. timorensis), both
distinguished by the presence ? large symmetrical shields on the crown of the
head, and by four upper labial shields being pitted. The former, which grows to
a length of about 11 feet, ranges from the Moluccas and Timor to New Guinea,
New Ireland, New Britain, and the North of Queensland; while the latter is
restricted to the islands of Timor ,n. Flores. The second subgroup, or the one
with from sixty-one to ninety- three sec les round the body, includes three species,
of which the Malayan reticulated python (P. reticulatus) has from sixty-nine to
seventy-nine scales in a row, and four upper labials with pits. This species, which
ranges from Burma and the Nicobar Islands to the Malayan region and Siam, is
one of the largest of the genus, occasionally reaching upwards of 30 feet in length.
In colour, it is light yellowish or brown above, ornamented with large circular






PYTHONS AND BOAS.



185



rhomboidal, or X-shaped dark markings ; while the head has a median black line,
and the under-parts are yellowish, with small brown spots on the sides. It is,
however, subject to considerable variation, a specimen from Siam in the London
Zoological Gardens showing bright yellow lines on the sides. Young specimens
show three longitudinal rows of light spots with black edges along the back,
Somewhat smaller is the African python (P. sebce), of tropical and South Africa,
which attains a length of about 23 feet, and has from eighty-one to ninety-three
scales in a row on the thickest part of the body, and only two of the labial shields



AUSTRALIAN DIAMOND-SNAKE ( Iiat. size).




pitted. This species occurs typically in West Afrit a, from which region came the
specimen represented in the illustration on p. 183 in the act of swallowing a bird ;
and it was long considered that the South African python or Natal rock-snake was
a distinct species. Its colour is pale brown b n with dark brown, black-edged,
and more or less wavy crossbars, usually cor lected by an interrupted or continuous
dark stripe running along each side of the back ; while the sides are marked with
large black spots and small dots. On the top of the head is a large triangular dark
brown blotch, which is bordered on each side by a light stripe commencing above the
nostril at the end of the muzzle, and passing above the eye ; and there is a dark
stripe on each side of the head, and a somewhat triangular blotch beneath each eye.



i88 SNAKES.

the smooth scales of the body ; by the presence of shields on the head ; and by the
labial shields being either devoid of pits or with only shallow ones. In form
the body is more or less compressed, and the tail either moderate or long; while
the eye is of medium size with a vertical pupil ; and the shields on the head may
be either small and irregular, or large and symmetrical.

These snakes are represented by nine species, the largest of which is the pale-




DOG-HEADED TREE-BOA (J liat. size).

headed tree-boa (Epicrates angulifer) of Cuba, attaining a length of about 7 feet
another well-known species being the streaked tree-boa (E. striatus), from San
Domingo and the Bahamas. The thick-necked tree-boa (E. cenchris), must,
however, be mentioned, its habitat ranging from Costa Rica to the northern
districts of Peru and Brazil. The figured species, which attains a length of about
5 feet, is either pale brown above with dark olive-brown spots separated by
narrow intervals from one another, or brown with wavy or zigzag yellowish
crossbands, not unfrequently margined with blackish brown. Each side of the



PYTHONS AND BOAS. 189

head usually has a more or less distinct streak behind the eye ; while the under-
parts are pale olive or yellowish, more or less spotted with brown or black.
Dog-Headed Closely allied to the last, the five species of the genus Corallus

Tree-Boa. are distinguished by having deep pits in the labial shields of both
the upper and lower lips. The body is compressed, with small smooth scales, and
the prehensile tail is either short or more or less elongated. This genus has a
somewhat remarkable distribution, four of its representatives being inhabitants
of tropical America, while the fifth (C. madagascariensis). which is distinguished
from the rest by the shortness of its tail, is restricted to Madagascar. The
dog-headed tree-boa (C'. caninus) is a native of the Guianas and Brazil, and
usually attains a length of some 5 feet, although it may be considerably larger.
It belongs to a group of two American species distinguished from the other kinds
inhabiting the same countries by the relatively shorter tail, which has only from
sixty-four to eighty-two shields on its inferior surface; whereas in the true
tree-boa (C. hortulanus), and another species, there are at least a hundred of
these shields. The species here figured is specially characterised by having the
scales arranged in sixty-one or seventy-one rows, and by the number of shields on
the under surface of the body ranging from one hundred and eighty-eight to two
hundred and nineteen, while those on the tail vary from sixty-four to seventy-nine.
In colour this snake is decidedly handsome, the upper-parts of the adult being
bright green, ornamented with irregular spots and crossbars of white, and the
under-parts bright yellow. In the young the ground-colour is yellowish, and the
white markings are edged with dark green or purplish black. Most abundant,
in the neighbourhood of the Amazons, this species becomes more rare in Guiana,
while southwards it likewise diminishes in numbers in lower Brazil. Feeding
principally upon birds, the dog-headed boa is an excellent swimmer, and has been
observed both in the Rio Negro and in the salt-water of the beautiful harbour
of Rio de Janeiro. Although it frequently visits the huts of the Brazilian negroes
in search of prey, it does not appear that this snake ever voluntarily attacks
human beings. If, however, it is driven to bay and unable to escape, it is capable
of inflicting very severe bites with its long front teeth, such wounds being
lifficult to heal.

Keeled A third genus of tree-boas (Enygrus) is distinguished from both

Tree-Boas. the preceding by the scales having distinct keels ; the labial shields
of the head being devoid of pits, and the tail short and prehensile, with a single
row of shields on its inferior surface. This genus is represented by four species
inhabiting the Moluccas, the Papuan region, and Polynesia.

This gigantic snake is the sole member of a group of several
genera, distinguished from the tree-boas by the teeth gradually
decreasing in size from the front to the back of the jaws without any marked
enlargement of those in the fore-part. Merely mentioning the allied tropical
American genera, Trachyboa, Ungalia, and Ungaliophis, the first and last of which
are each represented only by a single species, we may observe that the anaconda
is specially distinguished as a genus by the large size of the rostral shield of
the head, behind which one pair of the nasals come in contact with one another
in the middle line, and by the very small size of the smooth scales of the body.



1 9 SNAKES.

The head is markedly distinct from the neck ; the nostrils are directed upwards
and placed between three pairs of nasal shields, of which the hindmost are those
which meet in the middle line ; the small eye has the pupil vertical ; the body




THK Ilo.MK OF THE ANACONDA.



is cylindrical; and the tail is short and slightly prehensile, with a single row of
shields inferiorly. In colour the anaconda is greyish brown or olive above, with
either one or two series of large blackish transverse spots, and a single or double



PYTHONS AND BOAS. 191

row of lateral eye-like spots having whitish centres and blackish rims. The
upper part of the head is dark, and divided by a black streak terminating in a
point on the muzzle, from the lighter cheeks ; while another oblique black streak
runs on each side behind the eye ; the under-parts being whitish with blackish spots.
The anaconda (Euneces murinus) is an inhabitant of the Guianas, Brazil, and
North- Eastern Peru, and is essentially an inhabitant of tropical forest regions. That
it is the largest of all living snakes there can be little doubt, but the precise limits
of size to which it may occasionally attain cannot be ascertained. A stuffed
example in the British Museum has a total length of 29 feet, and the species is
commonly stated to reach 33 feet, while, if native reports are to be trusted,
individuals of much larger size are occasionally met with. Although naturalists
are generally indisposed to credit the existence of monsters of 40 feet, or even
more, we confess that personally we are unable to share their incredulity, as it is
very improbable that the largest specimens have come under European observation.
From all accounts, it appears that the anaconda generally spends more of its time
in the water than 011 land, frequently floating down rivers with the current,
and at other times lurking in quiet pools with only its head raised above the
surface of the water. In such situations, or resting on rocks, stranded tree trunks,
or sandbanks, it lies in wait for its prey. It, however, frequently leaves the
water to pass a longer or shorter period on shore, when it may be found either
in trees, among rocks, or even 011 hot sand ; and it appears that when in a tree
this snake will often dart down its head from a considerable height to seize a
passing peccary or other animal. Bates tells us that the anaconda will occasionally
seize human beings, and this statement is fully confirmed by other observers. In
Brazil, where water is abundant throughout the year, this snake is active at all
seasons, although it is stated to display the most activity during the hot months
of December, January, and February. In other districts, however, according to
Humboldt, during the dry season, it is in the habit of burying itself deep in the mud
of the dried-up rivers, where it is sometimes disinterred by the natives in a torpid
condition. Very little is known with regard to the breeding-habits of the anaconda.
Since, however, females have several times been killed, containing eggs with embryos
far advanced inside them, it would seem that the young are born alive. When they
first make their appearance in the world, the young are reported to take to the
water, although they soon leave it to pass a large portion of their time in trees.

Long supposed to be exclusively a tropical and South American
group, the true boas are common to the hotter regions of America
and Madagascar. From the anaconda, the boas may be distinguished by the
whole of the nasal shields being separated in the middle line by small scales. The
body may be either cylindrical or slightly compressed ; and the short and more or
less prehensile tail may have either the whole or a portion of the shields on its
lower surface arranged in a single series. In America the genus is represented
by five species, two of which range as far south as the inland districts of upper
Argentina. All species are characterised by having the loreal region of the head
covered either with a single small shield or with small scales, and by the number of
rows of shields on the under surface of the tail ranging from forty-five to sixty -nine.
On the other hand, in the Malagasy boas (Boa madayascariensis and dumerili)



192



SNAKES.



there are several shields on the same region of the head, while the number of rows
of shields beneath the tail is only from twenty to forty-one. The best known re-
presentative of the genus is the common boa, or boa-constrictor (B. constrictor},
which ranges in South America from Venezuela to upper Argentina. At times
reaching as much as 12 feet in length, it has the muzzle slightly prominent in the
adult, although obliquely truncated in the immature state. In general colour it is
pale brown on the upper-parts, with from fifteen to twenty dark brown crossbars,
which expand inferiorly, sometimes to such an extent as to become connected on




nat. size).



the sides of the body, and thus to surround oval or elliptical spots of the light ground-
colour ; the expanded portion of each bar having a light longitudinal line. On the
sides are a series of large light-centred dark brown spots, most of which alternate
with the crossbars ; and on the tail all the markings become relatively larger, of a
brick-red colour, margined with black, and separated by yellowish intervals. From
the muzzle to the nape runs a dark brown median streak, widening posteriorly, where
it may be looped; another bar of the same colour passes on each side of the head
through the eye, while there is a third below the latter, and the lips are marked
by such bars ; the rostral shield of the snout being also ornamented with a crescentic
blackish mark. The tinder-parts are yellowish, with spots and dots, or merely dots,
of black. The whole tone of coloration is dull, sombre, and adapted to harmonise
with the shades of brown, black, and yellow on the bark of tropical forest trees.



SAND-SNAKES. 193

Could we but see the boa during the night in the depths of its native forests
at which time alone it is thoroughly active we should doubtless obtain a very
different idea of the creature than that which we gather from the inspection in the
daytime of the lethargic specimens in menageries. Lying coiled on the branch of
some large tree, with its head projecting ready to be darted on its prey with the
rapidity of lightning, the boa is generally unobserved by the passing traveller
unless it happens to make a dart at an unfortunate dog belonging to his party.
Feeding generally on such mammals as agutis, pacas, rats, and mice, which are
destroyed in the manner from whence is derived its trivial name, the boa, when it
attains unusually large dimensions, is also capable of killing deer and large dogs ;
while it is always ready for such birds as it can capture, and does not disdain,
when in captivity, a meal of eggs. The stories of its killing adult human beings
and horses are, however, .mere fabrications. Nothing is known of the breeding-
habits of this snake and its kindred in a wild state ; but from observations made
on specimens in captivity, it appears that the eggs are generally hatched within
the body of the parent, although one instance is on record where young and eggs
were produced simultaneously. To European palates, snakes would probably be
highly unacceptable as food, however temptingly they might be dressed ; but in
Eastern South America, the flesh of the boa is regarded as a most dainty dish,
while its fat is reputed to be highly efficacious in the healing of various diseases.
The skin is used to ornament saddles and bridles, and for other decorative purposes.
None of the other members of the genus attain dimensions equal to those of the
common boa, the Malagasy species being the smallest of all.

Keel-Scaled The last representative of the section of the subfamily in which

Boa - the , head is well defined from the neck, and the tail more or less
prehensile, is the keel-scaled boa (Casarea dussumieri), of Round Island, near
Mauritius, distinguished as a genus by the keeling of the scales, and the long tail ;
its other general characters being similar to those of the true boas, except that the
isal shields of the head are separated by a pair of internasals. This snake, which
attains a length of about 4 feet, and has a prominent and obliquely truncated
mzzle, is either uniform pale brown above, or brown with two dark stripes and a
iteral series of small spots down the body, a dark streak 011 each side of the head
through the eye, and the under-parts either plain yellow or yellow spotted with
black, the under side of the tail always having such spots.

The snakes of this genus, together with those of three allied
Sand-Snakes.

genera, \vhich are the remaining members of the family, may be

distinguished at a glance from the boas and their allies by the gradual passage of
the head into the body without any constriction at the neck ; while they are
further characterised by the tail being, at most, only slightly prehensile. From
their allies, the sand-snakes are distinguished by the small scales being either
smooth or singly keeled, and by the head being covered with small shields, of
which the rostral is enlarged. The eye is small, and sometimes minute, with a
vertical pupil ; while the body is cylindrical ; and the very short tail, which is
frequently without any power of prehension, has a single row of shields on its
lower surface. These snakes are represented by seven species, with a geographical
distribution including Northern and Eastern Africa, and Southern and Central
VOL. v. i?



i 9 4



SNAA'KS.



Asia, as well as a part of the extreme south-west of Europe. The best known
species is the Egyptian sand-snake (Eryx jaculus), which has a length of about
2 feet, and is an inhabitant of the Ionian Islands, Greece, South- Western and
Central Asia, and the north of Africa. In colour it is very variable, the upper-
parts being in some examples pale greyish, reddish, or yellowish brown, ornamented
either with dark brown or blackish transverse blotches or alternating spots, while
in other cases the general colour is brown with pale spots. A dark streak runs
from each eye to the angle of the mouth; the under-parts are either uniform
white, or white with blackish dots; and there is a more or less distinct dark




EGYPTIAN SAND-SNAKE (J nat. size).

streak along each side of the tail. This species is exceeded in size by the Indian
sand-snake (E. johni), which attains a length of over a yard, and inhabits the
plains of North- Western, Central, and Southern India. This snake is generally
banded, but the young may be of a uniform pale coral-red colour. Although
resembling the boas in being nocturnal, these snakes are quite different in their
mode of life, inhabiting open sandy plains, and feeding on small mammals, lizards,
and worms. In search of their prey they frequently enter holes and crevices
among rocks, and they will also burrow in the sand. They are perfectly harmless,
and generally make no attempt to bite; but they are somewhat unsatisfactory
creatures in captivity, owing to their habit of lying concealed among the gravel



C YLINDER-SNAKES. 1 95

of their cage. The Indian species is frequently carried about by snake-charmers,
who are in the habit of mutilating the short tail so as to make it look like a
head ; whence arises the legend of two-headed snakes. A second Indian species
(E. conicus) was formerly referred to a separate genus (Gongylophis), on account
of having a series of keeled scales between the eyes.

Of the remaining members of the family, Lichanura, with one

Allied Gcncm

California!! species, differs from the sand-snakes by the smaller size
of the rostral shield, which is longer than wide ; while Charina, which is likewise
Californian, has the head covered with large shields. On the other hand, Bolieria,
as represented by a single species from Round Island, near Mauritius, differs from
all the other members of the group in having three or four keels on the scales, the
muzzle being covered with large shields.



Online LibraryRichard LydekkerThe new natural history (Volume 5) → online text (page 21 of 62)