The Romance of Natural History Part 4

It is just possible that the bird may yet haunt the inaccessible coast of East Greenland, but s.h.i.+ps sailing between that country and Iceland never meet with it at sea. Nor did Graah observe it during his toilsome researches east of Cape Farewell. The numerous fis.h.i.+ng craft that every season crowd the sh.o.r.es of Newfoundland and Labrador forbid the notion that it yet lingers there; for the great market-value set upon the bird and its eggs for collections would prevent its existence there from being overlooked. The numerous Polar voyages of discovery, and the annual fleets of whalers, would certainly have discovered it, if it still haunted the more northern regions. It is possible that a few isolated individuals may still survive; but it is the habit of the bird, as of most sea-fowl, to breed in society in bare seaward rocks, and the circ.u.mstance that no breeding station is known to be now frequented by the Great Auk renders it but too probable that it also must be cla.s.sed among the species that were.

The interest attached to this now extinct bird has induced some correspondents of the _Zoologist_ to attempt an enumeration of the specimens, both of the bird and of its eggs, (which from their great size, as well as from their rarity, have always had a value with collectors,) known to be preserved in cabinets. The result is that English collections contain 14 birds and 23 eggs; those of continental Europe, 11 birds and 20 eggs; the United States, 1 bird and 2 eggs:--the total being 26 birds and 45 eggs.

It would appear that the rock off the south of Iceland which was the chief breeding resort of the Great Auk, and which from that circ.u.mstance bore the name or "Geir-fulga Sker," sank to the level of the sea during a volcanic disturbance in or about the year 1830. "Such disappearance of the fit and favourable breeding-places of the _Alca impennis_," observes Professor Owen, "must form an important element in its decline towards extinction." One might think that there would be rocks enough left for the birds to choose a fresh station; but really we do not know what are the elements of choice in such a case: some peculiarities exist which make one particular rock to be selected by sea-fowl, when others apparently to us as suitable are quite neglected; but we do not know what they are. Possibly when Geir-fulga Sker sank, there was no other islet fit to supply the blank. Possibly, too, the submersion took place during the breeding season, drowning the eggs or young. If this was the case, it would indeed be "a heavy blow and great discouragement" to the dwindling Alcine nation.

Mr Darwin speaks of a large wolf-like Fox (_Canis antarcticus_) which at the time of his voyage was common to both the Falkland Islands, but absolutely confined to them. He says, "As far as I am aware, there is no other instance in any part of the world, of so small a ma.s.s of broken land, distant from a continent, possessing so large an aboriginal quadruped peculiar to itself. Their numbers have rapidly decreased; they are already banished from that half of the island which lies to the eastward of the neck of land between St Salvador Bay and Berkeley Sound.

Within a very few years after these islands shall have become regularly settled, in all probability this fox will be cla.s.sed with the Dodo, as an animal which has perished from the face of the earth."[67]

The Musk Ox (_Ovibos moschatus_), a long-haired ruminant, resembling what you would suppose a cross between a bull and a sheep might be,--formerly an inhabitant of Britain with the Elephant and the Hyena, but now found only on the polar margins of North America,--is becoming very scarce; and it is probable that before long its last representative will leave its bones with those of the lamented Franklin and his companions.

From the more perishable character of vegetable tissues we have far less data for determining the extinction of plant species; but a.n.a.logy renders it highly probable that these also have died out, and are dying in a corresponding ratio with animals. I am not aware that a single example can be adduced of a plant that has certainly ceased to exist during the historic era. But Humboldt mentions a very remarkable tree in Mexico, of which it is believed only a single specimen remains in a state of nature. It is the Hand-tree (_Cheirostemon platanoides_), a sterculaceous plant with large plane-like leaves, and with the anthers connected together in such a manner as to resemble a hand or claw rising from the beautiful purplish-red blossoms. "There is in all the Mexican free States only one individual remaining, one single primeval stem of this wonderful genus. It is supposed not to be indigenous, but to have been planted by a king of Toluca about five hundred years ago. I found that the spot where the Arbol de las Manitas stands is 8825 feet above the level of the sea. Why is there only one tree of the kind? Whence did the kings of Toluca obtain the young tree, or the seed? It is equally enigmatical that Montezuma should not have possessed one of these trees in his botanical gardens of Huaxtepec, Chapoltepec, and Iztapalapan, which were used as late as by Philip the Second's physician, Hernandez, and of which gardens traces still remain; and it appears no less striking that the Hand-tree should not have found a place among the drawings of subjects connected with Natural History, which Nezahual Coyotl, king of Tezcuco, caused to be made half a century before the arrival of the Spaniards."

There is an example of this interesting plant growing in one of the conservatories at Kew, but I do not know whence it was obtained. It has been a.s.serted that it grows wild in the forests of Guatemala.

Leaving plants out of consideration from lack of adequate data, we find that a considerable number of species of animals have certainly ceased to exist since man inhabited the globe. There have been, doubtless, many others that have shared the same fate, which we know nothing about. It is only within the last hundred years that we have had anything approaching to an acquaintance with the living fauna of the earth; yet, during that time some seven or eight creatures we know have been extinguished. Fully half of these,--the Auk, the Didunculus, the Notornis, and the Nestor,--within the last ten years! It would really seem as if the more complete and comprehensive an acquaintance with the animals of the world became, the more frequently this strange phenomenon of expiring species was presented to us. Perhaps it is not extravagant to suppose that--including all the invertebrate animals, the countless hosts of insects, and all the recondite forms that dwell in the recesses of the ocean--a species fades from existence every year. All the examples that have been given were either Mammalia or Birds, (_the Colossochelys_ only excepted:) now these, though the most conspicuous and best known, are almost the least populous cla.s.ses of living beings.

There is no reason whatever for concluding that the law of mortality of species does not extend to all the other cla.s.ses, vertebrate and invertebrate, in an equal ratio, so that my estimate will appear, I think, a very moderate one. Yet it is a startling thought, and one which the mind does not entertain without a measure of revulsion, that the pa.s.sing of every century in the world's history has left its fauna _minus_ a hundred species of animals that were denizens of the earth when it began. I was going to say "left the fauna so much _poorer_;" but that I am not sure of. The term would imply that the blanks are not filled up; and that, I repeat, I am not sure of. Probability would suggest that new forms are continually created to supply the lack of deceased ones; and it may be that _some_, at least, of the creatures ever and anon described as new to science, especially in old and well-searched regions, may be newly called into being, as well as newly discovered. It may be so, I say; I have no evidence that it is so, except the probability of a.n.a.logy; we know that the rate of mortality among _individuals_ of a species, speaking generally, is equalled by the rate of birth, and we may suppose this balance of life to be paralleled when the unit is a species, and not an individual. If the Word of G.o.d contained anything either in statement or principle contrary to such a supposition, I would not entertain it for a moment, but I do not know that it does. I do not know that it is anywhere implied that G.o.d created no more after the six days' work was done. His Sabbath-rest having been broken by the incoming of sin, we know from John v. 17, that He continued to work without interruption; and we may fairly conclude that progressive creation was included as a part of that unceasing work.

I know not whether my readers will take the same concern as I do in this subject of the dying-out of species, but to me it possesses a very peculiar interest. Death is a mysterious event, come when and how it will; and surely the departure from existence of a species, of a type of being, that has subsisted in contemporary thousands of individuals, for thousands of years, is not less imposingly mysterious than that of the individual exemplar.

We do not know with any precision what are the immediate causes of death in a species. Is there a definite limit to life imposed at first? or is this limit left, so to speak, to be determined by accidental circ.u.mstances? Perhaps both: but if the latter, what are those circ.u.mstances?

Professor Owen says:--"There are characters in land animals rendering them more obnoxious to extirpating influences, which may explain why so many of the larger species of particular groups have become extinct, whilst smaller species of equal antiquity have survived. In proportion to its bulk is the difficulty of the contest which the animal has to maintain against the surrounding agencies that are ever tending to dissolve the vital bond, and subjugate the living matter to the ordinary chemical and physical forces. Any changes, therefore, in such external agencies as a species may have been originally adapted to exist in, will militate against that existence in a degree proportionate to the size which may characterise the species. If a dry season be gradually prolonged, the large mammal will suffer from the drought sooner than the small one; if such alteration of climate affect the quant.i.ty of vegetable food, the bulky herbivore will first feel the effects of stinted nourishment; if new enemies be introduced, the large and conspicuous animal will fall a prey while the smaller kinds conceal themselves and escape. Small quadrupeds, moreover, are more prolific than large ones. Those of the bulk of the mastodons, megatheria, glyptodons, and diprotodons, are uniparous. The actual presence, therefore, of small species of animals in countries where larger species of the same natural families formerly existed, is not the consequence of degeneration--of any gradual diminution of the size--of such species, but is the result of circ.u.mstances which may be ill.u.s.trated by the fable of 'the Oak and the Reed;' the smaller and feebler animals have bent and accommodated themselves to changes to which the larger species have succ.u.mbed."[68]

"We do not steadily bear in mind," remarks Mr Darwin, "how profoundly ignorant we are of the condition of existence of every animal; nor do we always remember that some check is constantly preventing the too rapid increase of every organised being left in a state of nature. The supply of food, on an average, remains constant; yet the tendency in every animal to increase by propagation is geometrical; and its surprising effects have nowhere been more astonis.h.i.+ngly shewn, than in the case of the European animals run wild during the last few centuries in America.

Every animal in a state of nature regularly breeds; yet in a species long established, any _great_ increase in numbers is obviously impossible, and must be checked by some means. We are nevertheless seldom able with certainty to tell in any given species, at what period of life, or at what period of the year, or whether only at long intervals, the check falls; or again, what is the precise nature of the check. Hence probably it is, that we feel so little surprise at one, of two species closely allied in habits, being rare and the other abundant in the same district; or again, that one should be abundant in one district, and another, filling the same place in the economy of nature, should be abundant in a neighbouring district, differing very little in its conditions. If asked how this is, one immediately replies that it is determined by some slight difference in climate, food, or the number of enemies: yet how rarely, if ever, we can point out the precise cause and manner of action of the check! We are, therefore, driven to the conclusion that causes generally quite inappreciable by us, determine whether a given species shall be abundant or scanty in numbers.

"In the cases where we can trace the extinction of a species through man, either wholly or in one limited district, we know that it becomes rarer and rarer, and is then lost; it would be difficult to point out any just distinction between a species destroyed by man or by the increase of its natural enemies. The evidence of rarity preceding extinction, is more striking in the successive tertiary strata, as remarked by several able observers; it has often been found that a sh.e.l.l very common in a tertiary stratum is now most rare, and has even long been thought to be extinct. If, then, as appears probable, species first become rare and then extinct--if the too rapid increase of every species, even the most favoured, is steadily checked, as we must admit, though how and when it is hard to say--and if we see, without the smallest surprise, though unable to a.s.sign the precise reason, one species abundant, and another closely-allied species rare in the same district--why should we feel such great astonishment at the rarity being carried a step further to extinction? An action going on, on every side of us, and yet barely appreciable, might surely be carried a little further, without exciting our observation. Who could feel any great surprise at hearing that the Megalonyx was formerly rare compared with the Megatherium, or that one of the fossil Monkeys was few in number compared with one of the now living Monkeys? and yet, in this comparative rarity, we should have the plainest evidence of less favourable conditions for their existence. To admit that species generally become rare before they become extinct--to feel no surprise at the comparative rarity of one species with another, and yet to call in some extraordinary agent and to marvel greatly when a species ceases to exist, appears to me much the same as to admit that sickness in the individual is the prelude of death--to feel no surprise at sickness--but when the sick man dies to wonder, and to believe that he died through violence."[69]

Geographical distribution is an important element in this question of extinction. A species that is spread over a wide region is far more likely to survive than one which is confined to a limited district; and extraneous influences acting prejudicially will exterminate a species which is confined to an island much sooner than if it had a continent to retire upon. We have seen how the _Nestor_ Parrot became extinct in New Zealand, while it survived in Norfolk Island, because the former was colonised by the Maori race, while the latter remained in its virginity.

But how quickly did the poor Parrot succ.u.mb as soon as man set his foot on Norfolk and Philip Islands! And how brief was the lease of life accorded to the _Didunculus_, when once the "p.u.s.s.ies" found their way to the little Samoa isles!

Very many islands have a fauna that is to a great extent peculiar to themselves. I know that, in Jamaica, the Humming-birds, some of the Parrots, some of the Cuckoos, most of the Pigeons, many of the smaller birds, and, I think, all of the Reptiles, are found nowhere else. Nay, more, that even the smaller islands of the Antilles have each a fauna of its own, unshared with any other land;--its own Humming-birds, its own Lizards and Snakes; its own b.u.t.terflies and Beetles, its own Spiders, its own Snails, its own Worms. How likely are some of these very limited species to become extinguished! By the increasing aggressions of clearing and cultivating man; by slight changes of level; even by electric and meteoric phenomena acting very locally. I find that, in Jamaica, many of the animals peculiar to the island are not spread over the whole surface, limited as that is, but are confined to a single small district. In some cases, the individuals are but few, even in that favoured locality; how easily we may conceive of a season drier than ordinary, or wetter than ordinary, or a flood, or a hurricane of unusual violence, or a volcanic eruption, either killing outright these few individuals, or destroying their means of living, and so indirectly destroying them by starvation. And then the species has disappeared!

The common Red Grouse, so abundantly seen during the season hanging at every poulterer's and game-dealer's shop in London, is absolutely unknown out of the British Isles. It could not live except in wide, unenclosed, uncultivated districts; so that when the period arrives that the whole of British land is enclosed and brought under cultivation, the Grouse's lease of life will expire. We owe it to our hard-worked members of Parliament to hope that this condition of things may be distant.

[1] See my _Omphalos_,--_pa.s.sim_.

[2] The gradual but constant elevation of the bed of the Baltic, and the subsidence of that of the Pacific Ocean, are examples on a large scale.

[3] Gen. x. 5.

[4] _Chlamydotherium_, _Euryodon_, _Glossotherium_, _&c._

[5] Owen _On the Mylodon_.

[6] Perhaps the most complete and the most magnificent skeleton of this animal ever discovered, was exhumed in 1849 at Killowen, in Co. Wexford.

It was buried _only four feet below the surface_, between the vegetable mould and plastic clay. The roots of the black willow and German rush had entwined themselves round the bones, and some seeds, ascertained to be those of the wild cabbage, were found in the same bed. The dimensions of the skeleton were as follows:--Height, 12-1/2 feet to the tips of the horns, 7 feet to the top of the pelvis; expanse of horns 11 feet in a chord, or 13 feet 6 inches along the curve; palm of the antlers 2 feet 7 inches long by 1 foot 5 inches broad, some of the snags 2 feet 6 inches long; the face 1 foot 10-1/2 inches in length.

[7] _Annals of Nat. Hist._ xv.

[8] _Hist. Animals_, xvi. 17.

[9] _Nat. Hist._ ix. 10.

[10] _On the Mammoth or Fossil Elephant, &c._ London, 1819.

[11] _Testimony of the Rocks_, p. 97.

[12] See vol. i. p. 361, _supra_.

[13] Latrobe's _Mexico_, p. 192.

[14] _Nat. Voyage_, ch. v.

[15] _Nat. Voy._ ch. viii.

[16] _Compts Rendus_, Jan. 27, 1851.

[17] _Proc. Zool. Soc._, Jan. 27, 1852.

[18] "_The_ Humming-bird." Rather a vague mode of speaking, by a zoologist, of a genus which numbers more than three hundred species, varying in size from that of a swallow to that of a humble-bee. But probably he means one of the minuter species.

[19] _Proc. Zool. Soc._, Nov. 7, 1850.

[20] In the _Times_ of Feb. 21, 1861.

[21] _Proc. Roy. Soc._, X. x.x.xv. 50.

[22] _Ibid._ IX. xxix. 133.

[23] Because comparatively few readers, and especially the critics, will take the trouble to ascertain what an author really means if he attempt argumentation, generally supposing him to be proving something else than he propounds to himself, it may be needful to say, that I am not touching the question of the time required for the formation of the stratified rocks in general, but solely for that of the later Tertiary deposits.

[24] _Reports of a.n.a.lysis_, by Apjohn.

[25] Hart _On the Fossil Deer_.

[26] _Zoologist_, for 1846: Preface, p. 10.

[27] Mr Newman, _op. cit._ x.

[28] _Geilt._--According to O'Reilly, this word means "a wild man or woman,--one living in woods,"--a maniac. It may, however, have been figuratively applied to some very fierce or untameable creature, either quadruped or bird, which inhabited the woods. But that the _Simiae_, or monkey tribe, were not likely to have at any time inhabited so cold a country, one would have seen in the term an exceedingly apt expression for "the wild man of the woods." (Note by Translator.)

But, I venture to remind the reader, there was a veritable ape found in Britain during the very era of the Giant Deer, and of many of the now extant animals. I refer to the _Macacus pliocaenus_ (Owen) of the fresh-water deposits. Is it not just possible that the _Geilt_ of Ireland, the first-named animal in the poem, may have been this species?

A _Macacus_ still lingers in Europe, though the elephants and hippopotamuses have long deserted us.

[29] _Grib._--Probably the Osprey.

[30] These Wild Oxen are worthy of notice.