Alfred Russel Wallace
Travels on the Amazon
The total length of full-grown animals is seven feet. The intestines are very voluminous. The lungs are two feet long, and six or seven inches wide, very cellular, and when blown up, much resemble a Macintosh air-belt. The ribs are each nearly semicircular, arching back from the spine, so as to form a ridge or keel inside, and on the back there is a great depth of flesh. The bone is excessively hard and heavy, and can scarcely be broken. The dung resembles that of a horse.
The cow-fish feeds on grass on the margins of the rivers and lakes. It is captured either with the harpoon, or with strong nets, placed at the mouth of some lake, whence it comes at night to feed.
Though it has very small eyes, and minute pores for ears, its senses are very acute; and the fishermen say there is no animal can hear, see, and smell better, or which requires greater skill and caution to capture. When caught, it is killed by driving a wooden plug up its nostrils. The Indian fills his canoe full of water, and sinks it beneath the body; he then bales out the water, and paddles home with a load which requires a dozen men to move on shore. The meat is very good, and both for it and for the oil the animal is much sought after. It ascends most of the tributaries of the Amazon, but does not pass the falls or rapids.
B. Birds
The birds of the Amazon district are so numerous and striking, that it is impossible here to do more than mention a few of the most interesting and beautiful, so as to give some general idea of the ornithology of the district.
Among the birds of prey, the most conspicuous are the King Vulture (Sarcorhamphus papa), and the Harpy Eagle (Thrasaëtos harpyia), both of which are found in the whole district of the lower Amazon. There is also a great variety of eagles, hawks, kites, and owls, and probably between twenty and thirty species may be obtained in the country around Pará.
Those two fine eagles, the Spizaëtus ornatus and the Morphnus Guianensis, inhabit the Upper Amazon.
Among the smaller perching-birds, the yellow-breasted tyrant shrikes immediately attract attention, perched upon dead trees in the open grounds. In the forests the curious notes of the bush-shrikes (Thamnophilinæ) are often heard, and the ever-recurring vociferous cries of the great grey tyrant-flycatcher (Lipaugus simplex).
Several pretty little tanagers are found about Pará; but the exquisite little seven-coloured tanager (Calospiza tatao), and the scarcely less beautiful scarlet and black one (Rhamphocelis nigrogularis), do not occur till we reach the Rio Negro and the Upper Amazon.
The Chatterers form one of the most splendid families of birds, and we have on the Amazon some of the finest species, such as the Cotinga cayana, C. cœrulea, Phœnicurus carnifex, and P. militaris, which are found at Pará, and the C. Pompadoura, and P. nigrogularis on the Upper Amazon and Rio Negro.
The hang-nest Orioles, species of Cassicus, are numerous, and by their brilliant plumage of yellow or red and black, and their curious pendulous nests, give a character to the ornithology of the country.
Woodpeckers, kingfishers, and splendid metallic jacamars and trogons, are numerous in species and individuals. But of all the families of birds that inhabit this country, the parrots and the toucans are perhaps the most characteristic; they abound in species and individuals, and are much more frequently seen than any other birds.
From Pará to the Rio Negro I met with sixteen species of toucans, the most curious and beautiful of which is the Pteroglossus Beauharnasii, or "curl-crested Araçari," whose glossy crest of horny black curls is unique among birds.
Of parrots and paroquets I found at least thirty distinct species, varying in size from the little Psittaculus passerinus, scarcely larger than a sparrow, to the magnificent crimson macaws. In ascending the Amazon, large flocks of parrots are seen, every morning and evening, crossing the river to their feeding- or resting-places; and however many there may be, they constantly fly in pairs, as do also the macaws,—while the noisy little paroquets associate indiscriminately in flocks, and fly from tree to tree with a rapidity which few birds can surpass.
Though humming-birds are almost entirely confined to tropical America, they appear to abound most in the hilly and mountainous districts, and those of the level forests of the Amazon are comparatively few and inconspicuous. The whole number of species I met with in the Lower Amazon and Rio Negro, does not exceed twenty, and few of them are very handsome. The beautiful little Lophornis Gouldi, found rarely at Pará, and the magnificent Topaza pyra, which is not uncommon on the Upper Rio Negro, are, however, exceptions, and will bear comparison with any species in this wonderful family.
Probably no country in the world contains a greater variety of birds than the Amazon valley. Though I did not collect them very assiduously, I obtained upwards of five hundred species, a greater number than can be found all over Europe; and I have little hesitation in saying that any one collecting industriously for five or six years might obtain near a thousand different kinds.
C. Reptiles and Fishes
Like all tropical countries the Amazon district abounds in reptiles, and contains many of the largest size and most singular structure. The lizards and serpents are particularly abundant, and among the latter are several very venomous species; but the most remarkable are the boa and the anaconda, which reach an enormous size. The former inhabits the land, and though it is often found very large, yet the most authentic and trustworthy accounts of monstrous serpents refer to the latter, the Eunectes murinus of naturalists, which lives in or near the water. The Indians are aware of the generic distinction of these creatures, for while they call the former "Jiboa," the latter is the "Sucurujú."
The largest specimens I met with myself were not more than from fifteen to twenty feet long, but I have had several accounts of their having been killed, and measured, of a length of thirty-two feet. They have been seen very much larger, but, as may be supposed, are then very difficult to kill or secure, owing to their tenacity of life and their acquatic habits. It is an undisputed fact that they devour cattle and horses, and the general belief in the country is that they are sometimes from sixty to eighty feet long.6
Alligators of three or four distinct species abound in the Amazon, and in all its tributary streams. The smaller ones are eaten by the natives, the larger often devour them in return. In almost every village some persons may be seen maimed by these creatures, and many children are killed every year. The eggs of all the different kinds are eaten, though they have a very strong musky odour. The largest species (Jacare nigra) reaches a length of fifteen, or rarely of twenty feet.
The most interesting and useful reptiles of the Amazon are, however, the various species of fresh-water turtles, which supply an abundance of wholesome food, and from whose eggs an excellent oil is made. The largest and most abundant of these is the Tataruga, or great turtle of the Amazon, the Jurará of the Indians. It grows to the length of three feet, and has an oval flattish shell of a dark colour and quite smooth; it abounds in all parts of the Amazon, and in most places is the common food of the inhabitants.
In the month of September, as soon as the sandbanks begin to be uncovered, the females deposit their eggs, scraping hollows of a considerable depth, covering them over carefully, smoothing and beating down the sand, and then walking across and across the place in various directions for the purpose of concealment. There are such numbers of them, that some beaches are almost one mass of eggs beneath the surface, and here the Indians come to make oil. A canoe is filled with the eggs, which are all broken and mashed up together. The oil rises to the top, and is skimmed off and boiled, when it will keep, and is used both for light and for cooking. Millions of eggs are thus annually destroyed, and the turtles have already become scarce in consequence. There are some extensive beaches which yield two thousand pots of oil annually; each pot contains five gallons, and requires about two thousand five hundred eggs, which would give five millions of eggs destroyed in one locality.
But of those that remain, a very small portion are able to reach maturity. When the young turtles issue from the egg, and run to the water, many enemies are awaiting them. Great alligators open their jaws and swallow them by hundreds; the jaguars from the forest come and feed upon them; eagles and buzzards, and the great wood ibises attend the feast; and when they have escaped all these, there are many ravenous fishes which seize them in the stream.
The Indians catch the full-grown turtles, either with the hook, net, or arrow. The last is the most ingenious method, and requires the most skill. The turtle never shows its back above water, only rising to breathe, which it does by protruding its nostrils almost imperceptibly above the surface; the Indian's keen eyes perceive this, even at a considerable distance; but an arrow shot obliquely would glance off the smooth flat shell, so he shoots up into the air with such accurate judgment, that the arrow falls nearly vertically upon the shell, which it penetrates, and remains securely fixed in the turtle's back. The head of the arrow fits loosely on to the shaft, and is connected with it by a long fine cord, carefully wound round it; as the turtle dives, they separate, the light shaft forming a float or buoy, which the Indian secures, and by the attached cord draws the prize up into his canoe. In this manner almost all the turtles sold in the cities have been procured, and the little square vertical hole of the arrow-head may generally be seen in the shell.
Besides the great tataruga (Podocnemis expansa), there are several smaller kinds, also much used for food. The Tracaxa (Emys tracaxa, Spix) and the Cabeçudo (E. macrocephala, Spix) have been described by the French naturalists, Duméril and Bibron, as one species, under the name of Peltocephalus tracaxa; but they are quite distinct, and though their characters are perhaps not easy to define, they could never be confounded by any one who had examined them in the living state. They are found too in different localities. The tracaxa is abundant in the Amazon, in the Orinooko, and in the Guaviare, all white-water rivers, and very scarce in the Rio Negro. The cabeçudo is very abundant in the Rio Negro and in the Atabapo, but is not found in the Guaviare or the Amazon, appearing to be confined to the black-water streams. I obtained ten distinct kinds of river tortoises, or Chelydidæ, and there are also two or three kinds of land-tortoises inhabiting the adjacent district.
As might be expected in the greatest river in the world, there is a corresponding abundance and variety of fish. They supply the Indians with the greater part of their animal food, and are at all times more plentiful, and easier to be obtained, than birds or game from the forest.
During my residence on the Rio Negro I carefully figured and described every species I met with; and at the time I left fresh ones were every day occurring. The soft-finned fishes are much the most numerous, and comprise some of the best kinds of food. Of the Siluridæ I obtained fifty-one species, of Serrasalmo twenty-four, of Chalceus twenty-six, of Gymnotus ten, and of spinous-finned fishes (Acanthopterygia) forty-two. Of all kinds of fishes I found two hundred and five species in the Rio Negro alone, and these, I am sure, are but a small portion of what exist there. Being a black-water river, most of its fishes are different from those found in the Amazon. In fact, in every small river, and in different parts of the same river, distinct kinds are found. The greater part of those which inhabit the Upper Rio Negro are not found near its mouth, where there are many other kinds equally unknown in the clearer, darker, and probably colder waters of its higher branches. From the number of new fishes constantly found in every fresh locality and in every fisherman's basket, we may estimate that at least five hundred species exist in the Rio Negro and its tributary streams. The number in the whole valley of the Amazon it is impossible to estimate with any approach to accuracy.
D. Insects
To describe the countless tribes of insects that swarm in the dense forests of the Amazon would require volumes. In no country in the world is there more variety and beauty; nowhere are there species of larger size or of more brilliant colours. Here are found the extraordinary harlequin-beetle, the gigantic Prioni and Dynastes; but these are exceptions to the great mass of the Coleoptera, which, though in immense variety, are of small size and of little brilliancy of colour, offering a great contrast to the generally large-sized and gorgeous species of tropical Africa, India, and Australia. In the other orders the same rule holds good, except in the Hymenoptera, which contain many gigantic and handsome species. It is in the lovely butterflies that the Amazonian forests are unrivalled, whether we consider the endless variety of the species, their large size, or their gorgeous colours. South America is the richest part of the world in this group of insects, and the Amazon seems the richest part of South America. This continent is distinguished from every other by having a most extensive and peculiar family, the Heliconiidæ, of which not a single species is found in either Europe, Asia, Africa, or even North America (excepting Mexico). Another family, still more extensive, of exquisitely beautiful small butterflies, the Erycinidæ, is also almost peculiar to it, a few species only being found in tropical Asia and Africa. In both these peculiar families the Amazon is particularly rich, so that we may consider it as the headquarters of South America Lepidoptera.
Pará itself, for variety of species, is perhaps the best locality for diurnal Lepidoptera; six hundred distinct kinds may be obtained within a day's walk of the city. At Santarem I had increased my collection to seven hundred species, at Barra to eight hundred, and I should have brought home with me nine hundred species had my collections arrived in safety. Mr. Bates, who has paid more exclusive attention to insects, states that he has now obtained twelve hundred species,—a wonderful collection to be made by one person, in a country without any variation of climate or of physical features, and no part of it elevated five hundred feet above the level of the sea.
E. Geographical Distribution of Animals
There is no part of natural history more interesting or instructive than the study of the geographical distribution of animals.
It is well known that countries possessing a climate and soil very similar, may differ almost entirely in their productions. Thus Europe and North America have scarcely an animal in common in the temperate zone; and South America contrasts equally with the opposite coast of Africa; while Australia differs almost entirely in its productions from districts under the same parallel of latitude in South Africa and South America. In all these cases there is a wide extent of sea separating the countries, which few animals can pass over; so that, supposing the animal productions to have been originally distinct, they could not well have become intermixed.
In each of these countries we find well-marked smaller districts, appearing to depend upon climate. The tropical and temperate parts of America and Africa have, generally speaking, distinct animals in each of them.
On a more minute acquaintance with the animals of any country, we shall find that they are broken up into yet smaller local groups, and that almost every district has peculiar animals found nowhere else. Great mountain-chains are found to separate countries possessing very distinct sets of animals. Those of the east and west of the Andes differ very remarkably. The Rocky Mountains also separate two distinct zoological districts; California and Oregon on the one side, possessing plants, birds, and insects, not found in any part of North America east of that range.
But there must be many other kinds of boundaries besides these, which, independently of climate, limit the range of animals. Places not more than fifty or a hundred miles apart often have species of insects and birds at the one, which are not found at the other. There must be some boundary which determines the range of each species; some external peculiarity to mark the line which each one does not pass.
These boundaries do not always form a barrier to the progress of the animal, for many birds have a limited range, in a country where there is nothing to prevent them flying in every direction,—as in the case of the nightingale, which is quite unknown in some of our western counties. Rivers generally do not determine the distribution of species, because, when small, there are few animals which cannot pass them; but in very large rivers the case is different, and they will, it is believed, be found to be the limits, determining the range of many animals of all orders.
With regard to the Amazon, and its larger tributaries, I have ascertained this to be the case, and shall here mention the facts which tend to prove it.
On the north side of the Amazon, and the east of the Rio Negro, are found the following three species of monkeys, Ateles paniscus, Brachiurus satanas, and Jacchus bicolor. These are all found close up to the margins of the Rio Negro and Amazon, but never on the opposite banks of either river; nor am I able to ascertain that either of them have ever been found in any other part of South America than Cayenne or Guiana, and the eastern part of Venezuela, a district which is bounded on the south and west by the Amazon and Rio Negro.
The species of Pithecia, No. 14 of my list, is found on the west side of the Rio Negro for several hundred miles, from its mouth up to the river Curicuriarí, but never on the east side, neither is it known on the south side of the Upper Amazon, where it is replaced by an allied species, the P. irrorata (P. hirsuta, Spix), which, though abundant there, is never found on the north bank. These facts are, I think, sufficient to prove that these rivers do accurately limit the range of some species, and in the cases just mentioned, the evidence is the more satisfactory, because monkeys are animals so well known to the native hunters, they are so much sought after for food, and all their haunts are so thoroughly searched, and the localities for the separate kinds are so often the subject of communication from one hunter to another, that it is quite impossible that any well-known species can exist in a particular district, unknown to men whose lives are occupied in forming an acquaintance with the various tenants of the forests.
On the south side of the Lower Amazon, in the neighbourhood of Pará are found two monkeys, Mycetes beelzebub and Jacchus tamarin, which do not pass the river to the north. I have never heard of monkeys swimming over any river, so that this kind of boundary might be expected to be more definite in their case than in that of other quadrupeds, most of which readily take to the water.
Towards their sources, rivers do not form a boundary between distinct species; but those found there, though ranging on both sides of the stream, do not often extend down to the mouth.
Thus on the Upper Rio Negro and its branches are found the Callithrix torquatus, Nyctipithecus trivirgatus, and Jacchus (No. 21), none of which inhabit the Lower Rio Negro or Amazon; they are probably confined to the granitic districts which extend from Guiana across the sources of the Rio Negro towards the Andes.
Among birds it cannot be expected that we should find many proofs of rivers limiting their range; but there is one very remarkable instance of a genus, the three known species of which are separated by rivers, namely, the three species of genus Psophia, P. crepitans (Linn.), P. viridis (Spix), and P. leucoptera (Spix). The P. crepitans is the common trumpeter of Guiana; it extends into the interior all over the country, beyond the sources of the Rio Negro and Orinooko, towards the Andes, and down to the Amazon, both east and west of the Rio Negro, but is never found on the south side of the Amazon.
The P. viridis is found in the forests of Pará, at Villa Nova, on the south bank of the Amazon, and up to the Madeira, where it is found at Borba, on the east bank.
The P. leucoptera, a most beautiful white-backed species, is found also on the south bank of the Amazon, at São Paulo, at Ega, at Coarí, and opposite the mouth of the Rio Negro, but not east of the Madeira, where the green-backed species commences. These birds are all great favourites in the houses of the Brazilians, and all three may sometimes be seen domesticated at Barra, where they are brought by the traders from the different districts in which they are found. They are inhabitants of the dense forests, and scarcely ever fly; so that we see the reason why the rivers should so sharply divide the species, which, spreading towards each other from different directions, might otherwise become intermingled. It is not improbable that, if the two Brazilian species extend as far as the sources of the Madeira, they may be found inhabiting the same district.
Of the smaller perching-birds and insects, which doubtless would have afforded many interesting facts corroborative of those already mentioned, I have nothing to say, as my extensive collection of specimens from the Rio Negro and Upper Amazon, all ticketed for my own use, have been lost; and of course in such a question as this, the exact determination of species is everything.
The two beautiful butterflies, Callithea sapphira and C. Leprieuri, which were originally found, the former in Brazil, and the latter in Guiana, have been taken by myself on the opposite banks of the Amazon, within a few miles of each other, but neither of them on both sides of that river.
Mr. Bates has since discovered another species, named after himself, on the south side of the Amazon; and a fourth, distinct from either of them, was found by me high up in one of the north-western tributaries of the Rio Negro, so that it seems probable that distinct species of this genus inhabit the opposite shores of the Amazon.
The cock of the rock, Rupicola crocea, is, on the other hand, an example of a bird having its range defined by a geological formation, and by the physical character of the country. Its range extends in a curving line along the centre of the mountainous district of Guiana, across the sources of the Rio Negro and Orinooko, towards the Andes; it is thus entirely comprised in the granite formation, and in that part of it where there are numerous peaks and rocks, in which the birds make their nests.
Whether it actually reaches the Andes, or occurs in the same district with the allied R. Peruviana, is not known, but personal information obtained in the districts it inhabits, shows that it is confined to the narrow tract I have mentioned, between 1° south and 6° north latitude, and from the mountains of Cayenne to the Andes, south of Bogotá.
Another bird appears bounded by a geological formation. The common red-backed parrot, Psittacus festivus, is found all over the Lower Amazon, but, on ascending the Rio Negro, has its northern limit about St. Isabel, or just where the alluvial country ends and the granite commences; it also extends up the Japura, but does not pass over to the Uaupés, which is all in the granite district.
The fine blue macaw (Ara hyacinthina) inhabits the borders of the hilly country south of the Amazon, from the sea-coast probably up to the Madeira. Below Santarem, it is sometimes found close up to the banks of the Amazon, but is said never to cross that river. Its head-quarters are the upper waters of the Tocantíns, Xingú, and Tapajoz rivers.
As another instance of a bird not crossing the Amazon, I may mention the beautiful curl-crested Araçarí (Pteroglossus Beauharnaisii), which is found on the south side of the Upper Amazon, opposite the Rio Negro, and at Coarí and Ega, but has never been seen on the north side. The green Jacamar of Guiana also (Galbula viridis) occurs all along the north bank of the Amazon, but is not found on the south, where it is replaced by the G. cyanocollis and G. maculicauda, both of which occur in the neighbourhood of Pará.
