One Of
These Was A Squirrel (Sciurus Bangkanus), Closely Allied To Three
Other Species Inhabiting Respectively The Malay Peninsula,
Sumatra, And Borneo, But Quite As Distinct From Them All As They
Are From Each Other.
There were also two new ground thrushes of
the genus Pitta, closely allied to, but quite distinct from, two
other species inhabiting both Sumatra and Borneo, and which did
not perceptibly differ in these large and widely separated
islands.
This is just as if the Isle of Man possessed a peculiar
species of thrush and blackbird, distinct from the birds which
are common to England and Ireland.
These curious facts would indicate that Banca may have existed as
a distinct island even longer than Sumatra and Borneo, and there
are some geological and geographical facts which render this not
so improbable as it would at first seem to be. Although on the
map Banca appears so close to Sumatra, this does not arise from
its having been recently separated from it; for the adjacent
district of Palembang is new land, being a great alluvial swamp
formed by torrents from the mountains a hundred miles distant.
Banca, on the other hand, agrees with Malacca, Singapore, and the
intervening island of Lingen, in being formed of granite and
laterite; and these have all most likely once formed an extension
of the Malay peninsula. As the rivers of Borneo and Sumatra have
been for ages filling up the intervening sea, we may be sure that
its depth has recently been greater, and it is very probable that
those large islands were never directly connected with each other
except through the Malay peninsula. At that period the same
species of squirrel and Pitta may have inhabited all these
countries; but when the subterranean disturbances occurred which
led to the elevation of the volcanoes of Sumatra, the small
island of Banca may have been separated first, and its
productions being thus isolated might be gradually modified
before the separation of the larger islands had been completed.
As the southern part of Sumatra extended eastward and formed the
narrow straits of Banca, many birds and insects and some Mammalia
would cross from one to the other, and thus produce a general
similarity of productions, while a few of the older inhabitants
remained, to reveal by their distinct forms, their different
origin. Unless we suppose some such changes in physical geography
to have occurred, the presence of peculiar species of birds and
mammals in such an island as Banca is a hopeless puzzle; and I
think I have shown that the changes required are by no means so
improbable as a mere glance at the map would lead us to suppose.
For our next example let us take the great islands of Sumatra and
Java. These approach so closely together, and the chain of
volcanoes that runs through them gives such an air of unity to
the two, that the idea of their having been recently dissevered
is immediately suggested. The natives of Java, however, go
further than this; for they actually have a tradition of the
catastrophe which broke them asunder, and fix its date at not
much more than a thousand years ago. It becomes interesting,
therefore, to see what support is given to this view by the
comparison of their animal productions.
The Mammalia have not been collected with sufficient completeness
in both islands to make a general comparison of much value, and
so many species have been obtained only as live specimens in
captivity, that their locality has often been erroneously given,
the island in which they were obtained being substituted for that
from which they originally came. Taking into consideration only
those whose distribution is more accurately known, we learn that
Sumatra is, in a zoological sense, more neatly related to Borneo
than it is to Java. The great man-like apes, the elephant, the
tapir, and the Malay bear, are all common to the two former
countries, while they are absent from the latter. Of the three
long-tailed monkeys (Semnopithecus) inhabiting Sumatra, one
extends into Borneo, but the two species of Java are both
peculiar to it. So also the great Malay deer (Rusa equina), and
the small Tragulus kanchil, are common to Sumatra and Borneo, but
do not extend into Java, where they are replaced by Tragulas
javanicus. The tiger, it is true, is found in Sumatra and Java,
but not in Borneo. But as this animal is known to swim well, it
may have found its way across the Straits of Sunda, or it may
have inhabited Java before it was separated from the mainland,
and from some unknown cause have ceased to exist in Borneo.
In Ornithology there is a little uncertainty owing to the birds
of Java and Sumatra being much better known than those of Borneo;
but the ancient separation of Java as an island is well
exhibited by the large number of its species which are not found
in any of the other islands. It possesses no less than seven
pigeons peculiar to itself, while Sumatra has only one. Of its
two parrots one extends into Borneo, but neither into Sumatra. Of
the fifteen species of woodpeckers inhabiting Sumatra only four
reach Java, while eight of them are found in Borneo and twelve in
the Malay peninsula. The two Trogons found in Java are peculiar
to it, while of those inhabiting Sumatra at least two extend to
Malacca and one to Borneo. There are a very large number of
birds, such as the great Argus pheasant, the fire-backed and
ocellated pheasants, the crested partridge (Rollulus coronatus),
the small Malacca parrot (Psittinus incertus), the great helmeted
hornbill (Buceroturus galeatus), the pheasant ground-cuckoo
(Carpococcyx radiatus), the rose-crested bee-eater (Nyctiornis
amicta), the great gaper (Corydon sumatranus), and the green-
crested gaper (Calyptomena viridis), and many others, which are
common to Malacca, Sumatra, and Borneo, but are entirely absent
from Java. On the other hand we have the peacock, the green
jungle cock, two blue ground thrushes (Arrenga cyanea and
Myophonus flavirostris), the fine pink-headed dove (Ptilonopus
porphyreus), three broad-tailed ground pigeons (Macropygia), and
many other interesting birds, which are found nowhere in the
Archipelago out of Java.
Enter page number
PreviousNext
Page 54 of 112
Words from 54027 to 55067
of 114260
