The Malay Archipelago, by Alfred Russel Wallace

Chapter 27

The Natural History of the Moluccas.

THE Moluccas consist of three large islands, Gilolo, Ceram, and Bouru, the two former being each about two hundred miles long; and a great number of smaller isles and islets, the most important of which are Batchian, Morty, Obi, Ke, Timor–Laut, and Amboyna; and among the smaller ones, Ternate, Tidore, Kaióa, and Banda. They occupy a space of ten degrees of latitude by eight of longitude, and they are connected by groups of small islets to New Guinea on the east, the Philippines on the north, Celebes on the west, and Timor on the south. It will be as well to bear in mind these main features of extent and geographical position, while we survey their animal productions and discuss their relations to the countries which surround them on every side in almost equal proximity.

We will first consider the Mammalia or warm-blooded quadrupeds, which present us with some singular anomalies. The land mammals are exceedingly few in number, only ten being yet known from the entire group. The bats or aerial mammals, on the other hand, are numerous — not less than twenty-five species being already known. But even this exceeding poverty of terrestrial mammals does not at all represent the real poverty of the Moluccas in this class of animals; for, as we shall soon see, there is good reason to believe that several of the species have been introduced by man, either purposely or by accident.

The only quadrumanous animal in the group is the curious baboon-monkey, Cynopithecus nigrescens, already described as being one of the characteristic animals of Celebes. This is found only in the island of Batchian; and it seems so much out of place there as it is difficult to imagine how it could have reached the island by any natural means of dispersal, and yet not have passed by the same means over the narrow strait to Gilolo — that it seems more likely to have originated from some individuals which had escaped from confinement, these and similar animals being often kept as pets by the Malays, and carried about in their praus.

Of all the carnivorous animals of the Archipelago the only one found in the Moluccas is the Viverra tangalunga, which inhabits both Batchian and Bouru, and probably come of the other islands. I am inclined to think that this also may have been introduced accidentally, for it is often made captive by the Malays, who procure civet from it, and it is an animal very restless and untameable, and therefore likely to escape. This view is rendered still more probable by what Antonio de Morga tells us was the custom in the Philippines in 1602. He says that “the natives of Mindanao carry about civet-cats in cages, and sell them in the islands; and they take the civet from them, and let them go again.” The same species is common in the Philippines and in all the large islands of the Indo–Malay region.

The only Moluccan ruminant is a deer, which was once supposed to be a distinct species, but is now generally considered to be a slight variety of the Rusa hippelaphus of Java. Deer are often tamed and petted, and their flesh is so much esteemed by all Malays, that it is very natural they should endeavour to introduce them into the remote islands in which they settled, and whose luxuriant forests seem so well adapted for their subsistence.

The strange babirusa of Celebes is also found in Bouru; but in no other Moluccan island, and it is somewhat difficult to imagine how it got there. It is true that there is some approximation between the birds of the Sula Islands (where the babirusa is also found) and those of Bouru, which seems to indicate that these islands have recently been closer together, or that some intervening land has disappeared. At this time the babirusa may have entered Bouru, since it probably swims as well as its allies the pigs. These are spread all over the Archipelago, even to several of the smaller islands, and in many cases the species are peculiar. It is evident, therefore, that they have some natural means of dispersal. There is a popular idea that pigs cannot swim, but Sir Charles Lyell has shown that this is a mistake. In his “Principles of Geology” (10th Edit. vol. ii p. 355) he adduces evidence to show that pigs have swum many miles at sea, and are able to swim with great ease and swiftness. I have myself seen a wild pig swimming across the arm of the sea that separates Singapore from the Peninsula of Malacca, and we thus have explained the curious fact, that of all the large mammals of the Indian region, pigs alone extend beyond the Moluccas and as far as New Guinea, although it is somewhat curious that they have not found their way to Australia.

The little shrew, Sorex myosurus, which is common in Sumatra, Borneo, and Java, is also found in the larger islands of the Moluccas, to which it may have been accidentally conveyed in native praus.

This completes the list of the placental mammals which are so characteristic of the Indian region; and we see that, with the single exception of the pig, all may very probably have been introduced by man, since all except the pig are of species identical with those now abounding in the great Malay islands, or in Celebes.

The four remaining mammals are Marsupials, an order of the class Mammalia, which is very characteristic of the Australian fauna; and these are probably true natives of the Moluccas, since they are either of peculiar species, or if found elsewhere are natives only of New Guinea or North Australia. The first is the small flying opossum, Belideus ariel, a beautiful little animal, exactly line a small flying squirrel in appearance, but belonging to the marsupial order. The other three are species of the curious genus Cuscus, which is peculiar to the Austro–Malayan region. These are opossum-like animals, with a long prehensile tail, of which the terminal half is generally bare. They have small heads, large eyes, and a dense covering of woolly fur, which is often pure white with irregular black spots or blotches, or sometimes ashy brown with or without white spots. They live in trees, feeding upon the leaves, of which they devour large quantities, they move about slowly, and are difficult to kill, owing to the thickness of their fur, and their tenacity of life. A heavy charge of shot will often lodge in the slain and do them no harm, and even breaking the spine or piercing the brain will not kill them for some hours. The natives everywhere eat their flesh, and as their motions are so slow, easily catch them by climbing; so that it is wonderful they have not been exterminated. It may be, however, that their dense woolly fur protects them from birds of prey, and the islands they live in are too thinly inhabited for man to be able to exterminate them. The figure represents Cuscus ornatus, a new species discovered by me in Batchian, and which also inhabits Ternate. It is peculiar to the Moluccas, while the two other species which inhabit Ceram are found also in New Guinea and Waigiou.

In place of the excessive poverty of mammals which characterises the Moluccas, we have a very rich display of the feathered tribes. The number of species of birds at present known from the various islands of the Molluccan group is 265, but of these only 70 belong to the usually abundant tribes of the waders and swimmers, indicating that these are very imperfectly known. As they are also pre-eminently wanderers, and are thus little fitted for illustrating the geographical distribution of life in a limited area, we will here leave them out of consideration and confine our attention only to the 195 land birds.

When we consider that all Europe, with its varied climate and vegetation, with every mile of its surface explored, and with the immense extent of temperate Asia and Africa, which serve as storehouses, from which it is continually recruited, only supports 25l species of land birds as residents or regular immigrants, we must look upon the numbers already procured in the small and comparatively unknown islands of the Moluccas as indicating a fauna of fully average richness in this department. But when we come to examine the family groups which go to make up this number, we find the most curious deficiencies in some, balanced by equally striking redundancy in other. Thus if we compare the birds of the Moluccas with those of India, as given in Mr. Jerdon’s work, we find that the three groups of the parrots, kingfishers, and pigeons, form nearly one-third of the whole land-birds in the former, while they amount to only one-twentieth in the latter country. On the other hand, such wide — spread groups as the thrushes, warblers, and finches, which in India form nearly one-third of all the land-birds, dwindle down in the Moluccas to one-fourteenth.

The reason of these peculiarities appears to be, that the Moluccan fauna has been almost entirely derived from that of New Guinea, in which country the same deficiency and the same luxuriance is to be observed. Out of the seventy-eight genera in which the Moluccan land-birds may be classed, no less than seventy are characteristic of Yew Guinea, while only six belong specially to the Indo–Malay islands. But this close resemblance to New Guinea genera does not extend to the species, for no less than 140 out of the 195 land-birds are peculiar to the Moluccan islands, while 32 are found also in New Guinea, and 15 in the Indo–Malay islands. These facts teach us, that though the birds of this group have evidently been derived mainly from New Guinea, yet the immigration has not been a recent one, since there has been time for the greater portion of the species to have become changed. We find, also, that many very characteristic New Guinea forms lave not entered the Moluccas at all, while others found in Ceram and Gilolo do not extend so far west as Bouru. Considering, further, the absence of most of the New Guinea mammals from the Moluccas, we are led to the conclusion that these islands are not fragments which have been separated from New Guinea, but form a distinct insular region, which has been upheaved independently at a rather remote epoch, and during all the mutations it has undergone has been constantly receiving immigrants from that great and productive island. The considerable length of time the Moluccas have remained isolated is further indicated by the occurrence of two peculiar genera of birds, Semioptera and Lycocorax, which are found nowhere else.

We are able to divide this small archipelago into two well marked groups — that of Ceram, including also Bouru. Amboyna, Banda, and Ke; and that of Gilolo, including Morty, Batchian, Obi, Ternate, and other small islands. These divisions have each a considerable number of peculiar species, no less than fifty-five being found in the Ceram group only; and besides this, most of the separate islands have some species peculiar to themselves. Thus Morty island has a peculiar kingfisher, honeysucker, and starling; Ternate has a ground-thrush (Pitta) and a flycatcher; Banda has a pigeon, a shrike, and a Pitta; Ke has two flycatchers, a Zosterops, a shrike, a king-crow and a cuckoo; and the remote Timor–Laut, which should probably come into the Moluccan group, has a cockatoo and lory as its only known birds, and both are of peculiar species.

The Moluccas are especially rich in the parrot tribe, no less than twenty-two species, belonging to ten genera, inhabiting them. Among these is the large red-crested cockatoo, so commonly seen alive in Europe, two handsome red parrots of the genus Eclectus, and five of the beautiful crimson lories, which are almost exclusively confined to these islands and the New Guinea group. The pigeons are hardly less abundant or beautiful, twenty-one species being known, including twelve of the beautiful green fruit pigeons, the smaller kinds of which are ornamented with the most brilliant patches of colour on the head and the under-surface. Next to these come the kingfishers, including sixteen species, almost all of which are beautiful, end many are among the most brilliantly-coloured birds that exist.

One of the most curious groups of birds, the Megapodii, or mound-makers, is very abundant in the Moluccas. They are gallinaceous birds, about the size of a small fowl, and generally of a dark ashy or sooty colour, and they have remarkably large and strong feet and long claws. They are allied to the “Maleo” of Celebes, of which an account has already been given, but they differ in habits, most of these birds frequenting the scrubby jungles along the sea-shore, where the soil is sandy, and there is a considerable quantity of debris, consisting of sticks, shells, seaweed, leaves, &c. Of this rubbish the Megapodius forms immense mounds, often six or eight feet high and twenty or thirty feet in diameter, which they are enabled to do with comparative ease, by means of their large feet, with which they can grasp and throw backwards a quantity of material. In the centre of this mound, at a depth of two or three feet, the eggs are deposited, and are hatched by the gentle heat produced by the fermentation of the vegetable matter of the mound. When I first saw these mounds in the island of Lombock, I could hardly believe that they were made by such small birds, but I afterwards met with them frequently, and have once or twice come upon the birds engaged in making them. They run a few steps backwards, grasping a quantity of loose material in one foot, and throw it a long way behind them. When once properly buried the eggs seem to be no more cared for, the young birds working their way up through the heap of rubbish, and running off at once into the forest. They come out of the egg covered with thick downy feathers, and have no tail, although the wings are full developed.

I was so fortunate as to discover a new species (Megapodius wallacei), which inhibits Gilolo, Ternate, and Bouru. It is the handsomest bird of the genus, being richly banded with reddish brown on the back and wings; and it differs from the other species in its habits. It frequents the forests of the interior, and comes down to the sea-beach to deposit its eggs, but instead of making a mound, or scratching a hole to receive them, it burrows into the sand to the depth of about three feet obliquely downwards, and deposits its eggs at the bottom. It then loosely covers up the mouth of the hole, and is said by the natives to obliterate and disguise its own footmarks leading to and from the hole, by making many other tracks and scratches in the neighbourhood. It lays its eggs only at night, and at Bouru a bird was caught early one morning as it was coming out of its hole, in which several eggs were found. All these birds seem to be semi-nocturnal, for their loud wailing cries may be constantly heard late into the night and long before daybreak in the morning. The eggs are all of a rusty red colour, and very large for the size of the bird, being generally three or three and a quarter inches long, by two or two and a quarter wide. They are very good eating, and are much sought after by the natives.

Another large and extraordinary bird is the Cassowary, which inhabits the island of Ceram only. It is a stout and strong bird, standing five or six feet high, and covered with long coarse black hair-like feathers. The head is ornamented with a large horny calque or helmet, and the bare skin of the neck is conspicuous with bright blue and red colours. The wings are quite absent, and are replaced by a group of horny black spines like blunt porcupine quills.

These birds wander about the vast mountainous forests that cover the island of Ceram, feeding chiefly on fallen fruits, and on insects or crustacea. The female lays from three to five large and beautifully shagreened green eggs upon a bed of leaves, the male and female sitting upon them alternately for about a month. This bird is the helmeted cassowary (Casuarius galeatus) of naturalists, and was for a long time the only species known. Others have since been discovered in New Guinea, New Britain, and North Australia.

It was in the Moluccas that I first discovered undoubted cases of “mimicry” among birds, and these are so curious that I must briefly describe them. It will be as well, however, first to explain what is meant by mimicry in natural history. At page 205 of the first volume of this work, I have described a butterfly which, when at rest, so closely resembles a dead leaf, that it thereby escape the attacks of its enemies. This is termed a “protective resemblance.” If however the butterfly, being itself savoury morsel to birds, had closely resembled another butterfly which was disagreeable to birds, and therefore never eaten by them, it would be as well protected as if it resembled a leaf; and this is what has been happily termed “mimicry” by Mr. Bates, who first discovered the object of these curious external imitations of one insect by another belonging to a distinct genus or family, and sometimes even to a distinct order. The clear-winged moth which resemble wasps and hornets are the best examples of “mimicry” in our own country.

For a long time all the known cases of exact resemblance of one creature to quite a different one were confined to insects, and it was therefore with great pleasure that I discovered in the island of Bouru two birds which I constantly mistook for each other, and which yet belonged to two distinct and somewhat distant families. One of these is a honeysucker named Tropidorhynchus bouruensis, and the other a kind of oriole, which has been called Mimeta bouruensis. The oriole resembles the honeysucker in the following particulars: the upper and under surfaces of the two birds are exactly of the same tints of dark and light brown; the Tropidorhynchus has a large bare black patch round the eyes; this is copied in the Mimeta by a patch of black feathers. The top of the head of the Tropidorhynchus has a scaly appearance from the narrow scale-formed feathers, which are imitated by the broader feathers of the Mimeta having a dusky line down each. The Tropidorhynchus has a pale ruff formed of curious recurved feathers on the nape (which has given the whole genus the name of Friar birds); this is represented in the Mimeta by a pale band in the same position. Lastly, the bill of the Tropidorhynchus is raised into a protuberant keel at the base, and the Mimeta has the same character, although it is not a common one in the genus. The result is, that on a superficial examination the birds are identical, although they leave important structural differences, and cannot be placed near each other in any natural arrangement.

In the adjacent island of Ceram we find very distinct species of both these genera, and, strange to say, these resemble each other quite as closely as do those of Bouru The Tropidorhynchus subcornutus is of an earthy brown colour, washed with ochreish yellow, with bare orbits, dusky: cheeks, and the usual recurved nape-ruff: The Mimeta forsteni which accompanies it, is absolutely identical in the tints of every part of the body, and the details are copied just as minutely as in the former species.

We have two kinds of evidence to tell us which bird in this case is the model, and which the copy. The honeysuckers are coloured in a manner which is very general in the whole family to which they belong, while the orioles seem to have departed from the gay yellow tints so common among their allies. We should therefore conclude that it is the latter who mimic the former. If so, however, they must derive some advantage from the imitation, and as they are certainly weak birds, with small feet and claws, they may require it. Now the Tropidorhynchi are very strong and active birds, having powerful grasping claws, and long, curved, sharp beaks. They assemble together in groups and small flocks, and they haw a very loud bawling note which can be heard at a great distance, and serves to collect a number together in time of danger. They are very plentiful and very pugnacious, frequently driving away crows and even hawks, which perch on a tree where a few of them are assembled. It is very probable, therefore, that the smaller birds of prey have learnt to respect these birds and leave them alone, and it may thus be a great advantage for the weaker and less courageous Mimetas to be mistaken for them. This being case, the laws of Variation and Survival of the Fittest, will suffice to explain how the resemblance has been brought about, without supposing any voluntary action on the part of the birds themselves; and those who have read Mr. Darwin’s “Origin of Species” will have no difficulty in comprehending the whole process.

The insects of the Moluccas are pre-eminently beautiful, even when compared with the varied and beautiful productions of other parts of the Archipelago. The grand bird-winged butterflies (Ornithoptera) here reach their maximum of size and beauty, and many of the Papilios, Pieridae Danaidae, and Nymphalidae are equally preeminent. There is, perhaps, no island in the world so small as Amboyna where so many grand insects are to be found. Here are three of the very finest Ornithopterae — priamus, helena, and remiss; three of the handsomest and largest Papilios — ulysses, deiphobus, and gambrisius; one of the handsomest Pieridae, Iphias leucippe; the largest of the Danaidae, Hestia idea; and two unusually large and handsome Nymphalidae — Diadema pandarus, and Charaxes euryalus. Among its beetles are the extraordinary Euchirus longimanus, whose enormous legs spread over a space of eight inches, and an unusual number of large and handsome Longicorns, Anthribidae, and Buprestidae.

The beetles figured on the plate as characteristic of the Moluccas are: 1. A small specimen of the Euchirus longimanus, or Long-armed Chafer, which has been already mentioned in the account of my residence at Amboyna (Chapter XX.). The female has the fore legs of moderate length. 2. A fine weevil, (an undescribed species of Eupholus,) of rich blue and emerald green colours, banded with black. It is a native of Ceram and Goram, and is found on foliage. 3. A female of Xenocerus semiluctuosus, one of the Anthribidae of delicate silky white and black colours. It is abundant on fallen trunks and stumps in Ceram and Amboyna. 4. An undescribed species of Xenocerus; a male, with very long and curious antenna, and elegant black and white markings. It is found on fallen trunks in Batchian. 5. An undescribed species of Arachnobas, a curious genus of weevils peculiar to the Moluccas and New Guinea, and remarkable for their long legs, and their habit of often sitting on leaves, and turning rapidly round the edge to the under-surface when disturbed. It was found in Gilolo. All these insects are represented of the natural size.

Like the birds, the insects of the Moluccas show a decided affinity with those of New Guinea rather than with the productions of the great western islands of the Archipelago, but the difference in form and structure between the productions of the east and west is not nearly so marked here as in birds. This is probably due to the more immediate dependence of insects on climate and vegetation, and the greater facilities for their distribution in the varied stages of egg, pupa, and perfect insect. This has led to a general uniformity in the insect-life of the whole Archipelago, in accordance with the general uniformity of its climate and vegetation; while on the other hand the great susceptibility of the insect organization to the action of external conditions has led to infinite detailed modifications of form and colour, which have in many cases given a considerable diversity to the productions of adjacent islands.

Owing to the great preponderance among the birds, of parrots, pigeons, kingfishers, and sunbirds, almost all of gay or delicate colours, and many adorned with the most gorgeous plumage, and to the numbers of very large and showy butterflies which are almost everywhere to be met with, the forests of the Moluccas offer to the naturalist a very striking example of the luxuriance and beauty of animal life in the tropics. Yet the almost entire absence of Mammalia, and of such wide-spread groups of birds as woodpeckers, thrushes, jays, tits, and pheasants, must convince him that he is in a part of the world which has, in reality but little in common with the great Asiatic continent, although an unbroken chain of islands seems to link them to it.

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