Travel Reference
In-Depth Information
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 pro-
ductions 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 peculi-
ar 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 sug-
gested. 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 thou-
sand 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 nearly 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 re-
placed by Tragulus javanicus. The tiger, it is true, is found in Sumatra and Java, but not in
