Animals of the Past

Not so very long ago it was customary to account for changes in the past life of the globe by earthquakes, volcanic outbursts, or cataclysms of such appalling magnitude that the whole face of nature was changed, and entire races of living beings swept out of existence at once. But it is now generally conceded that while catastrophes have occurred, yet, vast as they may have been, their effects were comparatively local, and, while the life of a limited region may have been ruthlessly blotted out, life as a whole was but little affected. The eruption of Krakatoa shook the earth to its centre and was felt for hundreds of miles around, yet, while it caused the death of thousands of living beings, it remains to be shown that it produced any effect on the life of the region taken in its entirety.

Changes in the life of the globe have been in the main slow and gradual, and in response to correspondingly slow changes in the level of portions of the earth's crust, with their far-reaching effects on temperature, climate, and vegetation. Animals that were what is termed plastic kept pace with the altering conditions about them and became modified, too, while those that could not adapt themselves to their surroundings died out.

How slowly changes may take place is shown by the occurrence of a depression in the Isthmus of Panama, in comparatively recent geologic time, permitting free communication between the Atlantic and Pacific, a sort of natural inter-oceanic canal. And yet the alterations wrought by this were, so to speak, superficial, affecting only some species of shore fishes and invertebrates, having no influence on the animals of the deeper waters. Again, on the Pacific coast are now found a number of shells that, as we learn from fossils, were in Pliocene time common on both coasts of the United States, and Mr. Dall interprets this to mean that when this continent was rising, the steeper shore on the Pacific side permitted the shell-fish to move downward and adapt themselves to the ever changing shore, while on the Atlantic side the drying of a wide strip of level sea-bottom in a relatively short time exterminated a large proportion of the less active mollusks. And in this instance "relatively short" means positively long; for, compared to the rise of a continent from the ocean's bed, the flow of a glacier is the rapid rush of a mountain torrent.

Then, too, while a tendency to vary seems to be inherent in animals, some appear to be vastly more susceptible than others to outside influences, to respond much more readily to any change in the world about them. In fact, Professor Cook has recently suggested that the inborn tendency to variation is sufficient in itself to account for evolution, this tendency being either repressed or stimulated as external conditions are stable or variable.

The more uniform the surrounding conditions, and the simpler the animal, the smaller is the liability to change, and some animals that dwell in the depths of the ocean, where light and temperature vary little, if any, remain at a standstill for long periods of time.

The genus Lingula, a small shell, traces its ancestry back nearly to the base of the Ordovician system of rocks, an almost inconceivable lapse of time, while one species of brachiopod shell endures unchanged from the Trenton Limestone to the Lower Carboniferous. In the first case one species has been replaced by another, so that the shell of to-day is not exactly like its very remote ancestor, but that the type of shell should have remained unchanged when so many other animals have arisen, flourished for a time, and perished, means that there was slight tendency to variation, and that the surrounding conditions were uniform. Says Professor Brooks, speaking of Lingula: "The everlasting hills are the type of venerable antiquity; but Lingula has seen the continents grow up, and has maintained its integrity unmoved by the convulsions which have given the crust of the earth its present form."

Many instances of sudden but local extermination might be adduced, but among them that of the tile-fish is perhaps the most striking. This fish, belonging to a tropical family having its headquarters in the Gulf of Mexico, was discovered in 1879 in moderately deep water to the southward of Massachusetts and on the edge of the Gulf Stream, where it was taken in considerable numbers. In the spring of 1882 vessels arriving at New York reported having passed through great numbers of dead and dying fishes, the water being thickly dotted with them for miles. From samples brought in, it was found that the majority of these were tile-fish, while from the reports of various vessels it was shown that the area covered by dead fish amounted to somewhere between 5,000 and 7,500 square miles, and the total number of dead was estimated at not far from a billion. This enormous and widespread destruction is believed to have been caused by an unwonted duration of northerly and easterly winds, which drove the cold arctic current inshore and southwards, chilling the warm belt in which the tile-fish resided and killing all in that locality. It was thought possible that the entire race might have been destroyed, but, while none were taken for many years, in 1899 and in 1900 a number were caught, showing that the species was beginning to reoccupy the waters from which it had been driven years before.

The effect of any great fall in temperature on animals specially adapted to a warm climate is also illustrated by the destruction of the Manatees in the Sebastian River, Florida, by the winter of 1894-95, which came very near exterminating this species. Readers may remember that this was the winter that wrought such havoc with the blue-birds, while in the vicinity of Washington, D. C., the fish-crows died by hundreds, if not by thousands.

Fishes may also be exterminated over large areas by outbursts of poisonous gases from submarine volcanoes, or more rarely by some vast lava flood pouring into the sea and actually cooking all living beings in the vicinity. And in the past these outbreaks took place on a much larger scale than now, and naturally wrought more widespread destruction.

A recent instance of local extermination is the total destruction of a humming-bird, Bellona ornata, peculiar to the island of St. Vincent, by the West Indian hurricane of 1898, but this is naturally extirpation on a very small scale.

Still, the problems of nature are so involved that while local destruction is ordinarily of little importance, or temporary in its effects, it may lead to the annihilation of a species by breaking a race of animals into isolated groups, thereby leading to inbreeding and slow decline. The European bison, now confined to a part of Lithuania and a portion of the Caucasus, seems to be slowly but surely approaching extinction in spite of all efforts to preserve the race, and no reason can be assigned for this save that the small size of the herds has led to inbreeding and general decadence.

In other ways, too, local calamity may be sweeping in its effects, and that is by the destruction of animals that resort to one spot during the breeding season, like the fur-seals and some sea-birds, or pass the winter months in great flocks or herds, as do the ducks and elk. The supposed decimation of the Moas by severe winters has been already discussed, and the extermination of the great auk in European waters was indirectly due to natural causes. These birds bred on the small, almost inaccessible island of Eldey, off the coast of Iceland, and when, through volcanic disturbances, this islet sank into the sea, the few birds were forced to other quarters, and as these were, unfortunately, easily reached, the birds were slain to the last one.

From the great local abundance of their remains, it has been thought that the curious short-legged Pliocene rhinoceros, Aphelops fossiger, was killed off in the West by blizzards when the animals were gathered in their winter quarters, and other long-extinct animals, too, have been found under such conditions as to suggest a similar fate.

Among local catastrophes brought about by unusually prolonged cold may be cited the decimation of the fur-seal herds of the Pribilof Islands in 1834 and 1859, when the breeding seals were prevented from landing by the presence of ice-floes, and perished by thousands. Peculiar interest is attached to this case, because the restriction of the northern fur-seals to a few isolated, long undiscovered islands, is believed to have been brought about by their complete extermination in other localities by prehistoric man. Had these two seasons killed all the seals, it would have been a reversal of the customary extermination by man of a species reduced in numbers by nature.

In the case of large animals another element probably played a part. The larger the animal, the fewer young, as a rule, does it bring forth at a birth, the longer are the intervals between births, and the slower the growth of the young. The loss of two or three broods of sparrows or two or three litters of rabbits makes comparatively little difference, as the loss is soon supplied, but the death of the young of the larger and higher mammals is a more serious matter. A factor that has probably played an important rôle in the extinction of animals is the relation that exists between various animals, and the relations that also exist between animals and plants, so that the existence of one is dependent on that of another. Thus no group of living beings, plants or animals, can be affected without in some way affecting others, so that the injury or destruction of some plant may result in serious harm to some animal. Nearly everyone is familiar with the classic example given by Darwin of the effect of cats on the growth of red clover. This plant is fertilized by bumble bees only, and if the field mice, which destroy the nests of the bees, were not kept in check by cats, or other small carnivores, their increase would lessen the numbers of the bees and this in turn would cause a dearth of clover.

The yuccas present a still more wonderful example of the dependence of plants on animals, for their existence hangs on that of a small moth whose peculiar structure and habits bring about the fertilization of the flower. The two probably developed side by side until their present state of inter-dependence was reached, when the extinction of the one would probably bring about that of the other.

It is this inter-dependence of living things that makes the outcome of any direct interference with the natural order of things more or less problematical, and sometimes brings about results quite different from what were expected or intended.

The gamekeepers on the grouse moors of Scotland systematically killed off all birds of prey because they caught some of the grouse, but this is believed to have caused far more harm than good through permitting weak and sickly birds, that would otherwise have fallen a prey to hawks, to live and disseminate the grouse distemper.

The destruction of sheep by coyotes led the State of California to place a bounty on the heads of these animals, with the result that in eighteen months the State was called upon to pay out $187,485. As a result of the war on coyotes the animals on which they fed, notably the rabbits, increased so enormously that in turn a bounty was put on rabbits, the damage these animals caused the fruit-growers being greater than the losses among sheep-owners from the depredations of coyotes. And so, says Dr. Palmer, "In this remarkable case of legislation a large bounty was offered by a county in the interest of fruit-growers to counteract the effects of a State bounty expended mainly for the benefit of sheep-owners!"

Professor Shaler, in noting the sudden disappearance of such trees as the gums, magnolias, and tulip poplars from the Miocene flora of Europe has suggested that this may have been due to the attacks, for a series of years, of some insect enemy like the gipsy moth, and the theory is worth considering, although it must be looked upon as a possibility rather than a probability. Still, anyone familiar with the ravages of the gipsy moth in Massachusetts, where the insect was introduced by accident, can readily imagine what might have been the effect of some sudden increase in the numbers of such a pest on the forests of the past. Trees might resist the attacks of enemies and the destruction of their leaves for two or three years, but would be destroyed by a few additional seasons of defoliation.

Ordinarily the abnormal increase of any insect is promptly followed by an increase in the number of its enemies; the pest is killed off, the destroyers die of starvation and nature's balance is struck. But if by some accident, such as two or three consecutive seasons of wet, drought, or cold, the natural increase of the enemies was checked, the balance of nature would be temporarily destroyed and serious harm done. That such accidents may occur is familiar to us by the damage wrought in Florida and other Southern States by the unwonted severity of the winters of 1893, 1895, and 1899.

If any group of forest trees was destroyed in the manner suggested by Professor Shaler, the effects would be felt by various plants and animals. In the first place, the insects that fed on these trees would be forced to seek another source of food and would be brought into a silent struggle with forms already in possession, while the destruction of one set of plants would be to the advantage of those with which they came into competition and to the disadvantage of vegetation that was protected by the shade. Finally, these changed conditions would react in various ways on the smaller birds and mammals, the general effect being, to use a well-worn simile, like that of casting a stone into a quiet pool and setting in motion ripples that sooner or later reach to every part of the margin.

It is scarcely necessary to warn the reader that for the most part this is purely conjectural, for from the nature of the case it is bound to be so. But it is one of the characteristics of educated man that he wishes to know the why and wherefore of everything, and is in a condition of mental unhappiness until he has at least formulated some theory which seems to harmonize with the visible facts. And from the few glimpses we get of the extinction of animals from natural causes we must formulate a theory to fit the continued extermination that has been taking place ever since living beings came into the world and were pitted against one another and against their surroundings in the silent and ceaseless struggle for existence.

THE END.

INDEX

Æpyornis, egg of, 145, 148,* 147, 157
eggs found in swamps, 148;
found floating, 148
eggs used for bowls, 145
origin of fable of Roc, 144, 145

Alaskan Live Mammoth Story, 190-193, 197

Anomœpus tracks, 39

Apteryx egg, 147

Archæopteryx, description of, 77, 78
discovery of, 77
earliest known bird, 70
restoration, 89*
specimens of, 70,* 88
wing, 72,* 73

Archelon, a great turtle, 54


Basilosaurus, 60
See also Zeuglodon

Beehler, L. W., 209, 213

Birds, always clad in feathers, 71, 127
earliest, 70
Birds, first intimation of, 76
rarity of fossil, 86, 87
related to reptiles, 92
wings of embryonic, 73
with teeth, 79, 88

Bison, European, 231

Books of reference, xix, 17, 32, 47, 69, 89, 110, 137, 158, 176, 197, 218

Breeding of large animals, 233

Brontornis, size of leg-bones, 149

Brontosaurus, size of bones, 96,* 97,* 109

Brooks, W. K., on Lingula, 229

Buffalo legend, 216

Buttons as vestigial structures, 202


Carcharodon auriculatus, 66
teeth, 66
megalodon, 65
estimated size, 66
teeth, 65, 67

Carson City footprints, 45

Casts, how formed, 10, 11

Cats and clover, 234

Cephalaspis, 24*

Ceratosaurus, habits, 106
restoration, 106*
skull, 110*

Changes in Nature slow, 227

Cheirotherium, 43

Chlamydosaurus, 129

Claosaurus. See Thespesius

Climate, changes in western United States, 174

Clover and cats, 234

Cold, effects of, on animals, 230, 231, 233

Cold winters, 230

Collecting fossils, 17, 112-116

Color of large land animals, 134
of young animals, 136

Covering of extinct animals sometimes indicated, 131, 132

Coyotes, effect of their destruction on fruit, 236


Dall, W. H., theory as to extinction of mollusks, 227

Dinosaurs, bones of, 109, 110
brain of, 93
collections of, 109
compared to marsupials, 95
first discovered, 90
food required by, 98
hip-bones mistaken for shoulder-blade, 120
Professor Marsh's epitaph for, 222
range, 92
recognized as new order of reptiles, 91
related to ostrich and alligator, 91
size of, 95, 96, 98
tracks, ascribed to birds, 38

Dinotherium, 200

Diplodocus, estimated weight, 99
supposed habits, 99


Egg of Æpyornis, 147, 148;
Apteryx, 147;
Ostrich, 146;
Moa, 148

Eggs, casts of, 87

Elephant, size, 180
size of tusks, 181, 182

Elephas ganesa, tusks, 196

Encrustations, 14

Extermination. See Extinction

Extinction, ascribed to great convulsions, 225
ascribed to primitive man, 188, 224
of Dinosaurs, 221
local, 225
by man, 224, 225
of Marine Reptiles, 222
often unaccountable, 222, 223
of Pliocene rhinoceros, 232
sometimes evolution, 221, 226
of Titanotheres, 222


Feathers, imprints of, 76, 132

Fishes, abundance of, 25
armored, 23, 24, 25, 28
collections of, 32
killed by cold, 230
killed by volcanoes, 231

Fish-crows, killed by cold, 231

Flesh does not petrify, 10

Flightless birds, absent from Tasmania, 155
present distribution, 154, 155
relation between flightlessness and size, 156

Folds and frills, 129

Footprints, collections of, 47
books on, 47
See also under Tracks

Fossil birds, rarity of, 86

Fossil man, 13

Fossilization a slow process, 10

Fossils, conditions under which they are formed, 5, 7
collecting, 112-116
definition of, 1
deformation of, 16
impressions, 2, 3
not necessarily petrifactions, 2
preparation of, 117-119
why they are not more common, 5, 15, 16

Fowls, muscles of, 81

Frill of Triceratops, 102

Fur-seals killed by ice-floes, 233


Gar pikes, destruction of, 26

Giant birds, reasons for distribution and flightlessness, 153

Giant Moa, 141
leg compared with that of horse, 152*

Giant Sloth, domesticated by man, 224
struggle between, 46

Giant Sloth, tracks at Carson City, 46

Gilfort, Robert, 157

Great Auk, extermination of, 232

Grouse on Scotch moors, 235


Hawkins, B. W., restorations by, 137

Hesperornis, description of, 80
impressions of feathers, 132
position of legs, 83, 84
restoration of, 82*

Hippotherium, 166, 167

Hoactzin, habits of, 74, 75*

Horn does not petrify, 130

Horse, abundant in Pleistocene time, 164
books on, 176
of bronze age, 163, 167
collections of fossil, 176
development of, 167, 168,* 175
differences between fossil and living, 163
early domestication, 165
evidence as to genealogy, 170-173
extra-toed, 172, 173
found in South America in 163, 165
of Julius Cæsar, 172
none found wild in historic times, 165
Pliocene, 166
possibility of existence in America up to the time of its discovery, 169, 170
primitive, 160, 161*

Horse, sketched by primitive man, 163
teeth of, 170
three-toed, 166

Humming-bird, exterminated by hurricane, 231

Hydrarchus, 62*

Hyracotherium, 160, 161,* 170, 174


Ichthyosaurs, silhouettes of, 132

Iguanodons, found at Bernissart, 104

Impressions of feathers, 131
of scales, 131
of skin, 131

Inbreeding, effects of, 231, 232

Information, sources of, xvi

Innuits, habits, 192

Interdependence of animals and plants, 234, 235, 238

Ivory, fossil, 2, 4, 188, 189


Jaw of Mosasaur, 54*
of reptiles, 53


Killing of the Mammoth, story, 177, 193

Kimmswick, deposit of Mastodon bones, 209

Knight, Charles R., restorations by, xviii, 136

Koch's Hydrarchus, 61, 62*
Missourium, 207,* 208


Leaves, impressions of, 3, 13

Leg of Brontornis, 149*

Leg of the Great Brontosaurus, 96*
of Giant Moa, 152*
position in Hesperornis, 83
position in ducks, 84

Lenape Stone, 215, 216, 219*

Life, earliest traces of, 21, 34

Lingula, antiquity of, 228
Professor Brooks on, 229

Loricaria, 24*


Mammoth, adapted to a cold climate, 134
Alaskan Live, Story, 190
believed to live underground, 178
bones taken for those of giants, 185
contemporary with man, 189
derivation of name, 178
description, 179
discovery of entire specimens, 183, 187
distribution, 184, 186
drawn by early man, 189, 197*
entire specimens obtainable, 194
reasons for extermination, 188
killing of the, 177
literature on, 197
misconception as to size, 179
mounted skeleton, 179
not now living, 190
preservation of remains, 187
skeletons in Alaska, 181, 195

Mammoth, in Chicago Academy of Sciences, 179
at St. Petersburg, 183*
restoration, 176*
size, 179, 180, 181
size of tusks, 181, 196
teeth, 196, 199*
teeth dredged in North Sea, 184
tusks brought into market, 188, 189

Man contemporary with Mammoth, 189
fossil, 13
of Guadeloupe, 13

Manatees killed by cold, 230

Marsh, Prof. O. C., collection of fossil horses, 176
on Dinosaurs, 222
on toothed birds, 79, 89

Mastodon, bones taken for those of giants, 205
thought to be carnivorous, 206
covering, 210
description, 210
distribution, 203, 210, 212
extinction, 212
literature, 218
and man, 215, 216
first noticed in America, 204
origin unknown, 202
remains abundant, 208, 209
remains in Ulster and Orange counties, New York, 204, 206
restoration, 210*

Mastodon, size, 211
skeletons on exhibition, 218
species, 203
teeth, 198, 199,* 218
tusks, 199, 200

Mesohippus, 167

Mimicry, not conscious, 128

Missourium of Koch, 207,* 208

Moas, collections of, 156, 157
contemporary with man, 143, 144
deductions from distribution, 143
destruction of, 143, 144
discovery of bones, 140
elephant-footed, 142
feathers of, 141
Giant, 141
supposed food of, 142
legends of, 139, 140
literature, 158
scientific names, 146
size of, 141
species of, 141

Moloch, an Australian lizard, 100*

Mosasaurs, abundance of, in Kansas, 52
books on, 69
collections of, 68
extinction of, 56
first discovery, 50
jaw of, 54*

Mosasaurs, range of, 49
restoration, 52*
size of, 49, 50

Mylodon tracks at Carson City, 45


Names, scientific, reasons for using, xvi, xvii

Nature, balance of, 238

Nuts, fossil, 11


Oldest animals, 21
vertebrates, 19, 22

Ostrich egg, 147

Over-specialization, 221, 222


Peale, C. W., 205

Peale, Rembrandt, 205, 206

Pelican, mandible, 53

Penguins, depend on fat for warmth, 127
feathers highly modified, 128
swim with wings, 80

Petrified bodies, 10

Phororhacos, description of, 149
mistaken for mammal, 149
Patagonian bird, 148
related to heron family, 152
restoration, frontispiece
skull, 150, 151*

Protohippus, 166

Pteraspis, 28

Pterichthys, 25, 28, 32*
mistaken for crab, 25

Pterodactyls, impressions of wings, 133
from Kansas, 55
wing, 72*

Pycraft, W. P., restoration of Archæopteryx, 89


Radiolarians, 15, 17*

Reconstruction of animals, 127, 130, 134

Reptiles, fasting powers of, 98
growth throughout life, 102
jaws, 53

Restorations, xviii
Archæopteryx, 89*
Ceratosaurus, 106*
Hesperornis, 82*
Mammoth, 176*
Mastodon, 210*
Phororhacos, frontispiece
progress in, 137
Stegosaurus, 108*
Thespesius, 90*
Triceratops, 126*
Tylosaurus, 52*

Reversion of fancy stock, 171

Rhinoceros, exterminated by cold, 232

Roc, legend of, 144, 145

Rocks, thickness of sedimentary, 20

Ruffles on dresses, 202


Schuchert, Charles, on collecting fossils, 17
collector of Zeuglodon bones, 63

Seals, covering of, 128

Sea-serpent, belief in, 56
possibility of existence, 57

Shaler, Professor, on changes in Miocene flora of Europe, 236, 237

Sharks, early, 31
Great-toothed, 65
known from spines and teeth, 29
Port Jackson, 29
teeth of, 69
White, or Man-Eater, 65

Skeleton, basis of all restorations, 127
best testimony of animal's relationships, 124
information to be derived from, 120, 122, 123, 124, 125, 126, 127
a problem in mechanics, 102, 124
reconstruction of, 120
relation of, to exterior of animal, 121, 127
of Triceratops, 103,* 121

Spines and plates, 130

Stegosaurus, description of, 106
restoration of, 108*

Survival of the fittest, 173


Teeth, birds with, 79
of gnawing animals, 169, 200
of grass-eaters, 169

Teeth, of horse, 170
of mammoth, 198, 199*
of mastodon, 198, 199*
of sharks, 29, 30
of Thespesius, 105

Thespesius, abundance of, 104, 105
brain of, 93
(Same as Claosaurus)
engulfed in quicksand, 8
impressions of skin, 132
restoration of, 90*
teeth of, 105
at Yale, 109

Tiger, preying on reindeer, 134

Tile-fish, destruction of, 230

Titanichthys, 28, 29

Toothed birds, collections of, 88
discovery of, 79

Townsend C. H., 190-192

Tracks, ascribed to birds, 38
ascribed to giants, 45
animals known from, 41
collections of, 47
of Connecticut Valley, 37
deductions from, 44
of Dinosaurs, 38,* 40,* 41, 47*
discovery in England and America, 37, 42
how formed, 35, 40
at Hastings, 44

Tracks, of Mylodon, 46
of worms, 3, 33

Triceratops, brain, 94
broken horn, 102
description, 100, 101
restoration, 126*
skeleton, 103*

Tufa, 14

Tukeman, killing of the Mammoth, 177, 193


Variation in animals, 228

Vertebrates, oldest, 22

Vestigial structures, 201, 202

Volcanic outbursts, 231, 232


Webster, F. S., on destruction of gar pikes, 26

White, C. A., on the nature and uses of fossils, 17

White Shark, 65

Wings, 71, 72,* 73
of embryonic birds, 73

Wood, fossil, 9, 10

Worm trails, 3, 33


Yucca, fertilization, 235


Zeuglodon, abundance of remains, 60
same as Basilosaurus
description, 58, 63
habits, 59

Zeuglodon, Koch's restoration, 62
name, 58, 69
once numerous, 60
size, 58
specimen of, 68
structure of bones, 64
teeth, 58, 69*