the ‘courthouse’. For six weeks he was confined indoors while his feet healed from
sandfly bites that had swelled up and become infected. He spent his time writing
up his notes and preparing his specimens for shipment. He had 9000 specimens, of
which about 1600 were distinct species and worth a fortune in London. The Macassan
traders were now loading their prahus for the return voyage on the east monsoonal
winds and he would sail with them back to Macassar with his treasures. During his
time in Aru, Wallace had made the acquaintance of a strange and little-known race of
men, had become familiar with the archipelago traders, had revelled in the delights
of exploring a new flora and fauna, and had been able to view the magnificent greater
birds of paradise performing their dancing rituals in their native forests.
On the return voyage to Macassar, sitting in his small bamboo and thatch cabin
while working on his notes, Wallace had plenty of time to consider what he had
observed. He knew that the birds of paradise, along with the other birds on Aru, were
also found in New Guinea. He noted the similarities between the fauna of Aru and
New Guinea, and the fauna of New Guinea and Australia. Apart from bats (which
migrate long distances) and pigs (introduced by man) all the mammals he found on
Aru were marsupials, such as the dusky pademelon or Aru islands wallaby, which
together with the cockatoos, cassowaries and brush turkeys are typically Australian
fauna and he wrote:
The fact of the Aru Islands having once been connected to New Guinea does not rest on this
evidence alone. There is such a striking resemblance between the productions of the two
countries as only exists between portions of a common territory. I collected one hundred
species of land-birds in the Aru Islands, and about eighty of them have been found on the
mainland of New Guinea. Among these are the great wingless cassowary, two species of
heavy brush turkeys, and two of short-winged thrushes, which could certainly not have
passed over 150 miles of open sea from the coast of New Guinea ... Again a true kangaroo
is found in Aru ... and another small marsupial animal (Perameles doreyanus) is common
to Aru and New Guinea.Wallace could not help but be intrigued by the similarities of the native fauna of
Aru to that of New Guinea and of them both to Australian fauna. Of course we now
know that New Guinea and Aru carry Australian fauna because they were always part
of the Australian continent and although they now stand above sea level as wrinkles
on its continental margin they were certainly connected during the lowering of sea
levels in the different ice ages.
Back in Macassar Wallace prepared a paper to send to London for the Annals and
Magazine of Natural History entitled ‘On the Natural History of the Aru Islands’.
Alfred Russel Wallace – The Voyage to the Aru Islands 157