SQUIRRELS, WOODCHUCKS AND BEAVERS
Squirrels in form and activities are much alike all over the world, and are absent only from Australia and Madagascar. The long, bushy tail that makes so excellent a blanket as it is wrapped about their bodies when curled up asleep, is the badge and pride of the tribe. They inhabit hollows in the trees or sometimes holes among their roots, and in summer make globular nests of leaves and twigs in which the young are nursed and trained. Nuts form their staple food, but berries, fruits, roots, funguses, insect grubs, etc., offer changes in fare with the recurring seasons. Sometimes great ingenuity is displayed in getting at this food. Some species are arrant robbers of birds' nests, and now and then kill and eat small birds and mammals; and the older males are resolutely kept away from their babies by the mothers for fear of cannibalism. This catholic appetite, and their willingness to wander from place to place in search of things seasonable, enable squirrels to find food of some sort every month of the year, yet most species have the forethought to lay up in more or less secret places a winter supply of provender; consequently no species of Sciurus hibernates, strictly speaking.
This storing of winter provender is a matter that has been regarded with more general interest, perhaps, than any other feature of animal economy, and is mainly manifested among the rodents, although practiced in a limited way by some others, as for instance, by weasels and foxes. It looks like conscious foresight of the famine time to come, but it is no doubt in the main, if not wholly, instinctive, since the young, who have had no experience of the winter's scarcity or imprisonment ahead, make suitable preparations. It seems to me that this habit, so necessary to the existence of small, vegetarian creatures in cold climates, arose in some such way as this:
The little animals that store supplies designed to keep them alive through the winter are those whose food is for one reason or another unobtainable then. Remember, also, that they are feebly endowed with powers either for defense or for escape outside their homes, and when gathering their food must not loiter much to eat as they go, but must pick up what they can carry and hasten to the safety of their doorways. This is the reason why surviving species of such animals have acquired cheek pouches, in which they can transport a fair meal of their food to be eaten at home at leisure.
During the larger part of the year food is scant, and these rodents get into the way of picking up every bit they can find, and seem so restless and energetic that some of them, such as the viscachas and pack rats, accumulate about their burrows or nests quantities of inedible things, moved, apparently, by mere objectless acquisitiveness. The search for food, the foremost occupation and anxiety of these small wood-folk, would be increasingly stimulated as the ripening season of the seeds and nuts on which they depend advanced, and the impulse to incessant industry, so necessary in the poorer parts of the year, would now be overworked, and each animal, in his haste to be up and doing, would constantly bring home more food than would be consumed, so that it would pile up in the accustomed "dining room." The gradual failure of outdoor supplies, as winter came on, would lead to the eating, with increasing frequency, of those fragments casually saved in and about the burrow or house, which, from their nature, would not have decayed. The animal which had been most busy and clever in food gathering would own the largest amount of the leavings of these autumnal feasts. Having the most food he would be among those of the colony or neighborhood strongest and most likely to survive, and to give to his offspring the tendency to strength and industry which had been his salvation. This would be continued and shaped by the process of natural selection into a valuable, instinctive habit of gathering nonperishable food in large quantities every autumn, and thus providing themselves with stores to last through the coming winter; but it does not follow that the squirrels and mice are conscious of this wise forethought.
The striped, chattering, ever-busy chipmunks, of which America possesses several delightful species, although able to ascend into trees, and frequently doing so, are groundlings, and fond of rocky places into whose crevices they can quickly rush when an enemy is seen or heard; hence their fondness for the stone walls that in the East divide farm fields, and in general they are more inclined to associate with man and his works than are the tree squirrels, although the grays lend themselves readily to the semidomestication of residence in village streets and city parks, as the red never does. The chipmunks dig long underground tunnels, enlarged here and there into chambers serving as bedrooms, storerooms for food, and refuse bins; and the northwestern species are so numerous that between what they eat and waste in gardens and grainfields and the bad runways for water their galleries make, they are justly regarded as a pest.
These pretty but troublesome chipmunks are called "gophers" in some parts of the West, but that name is more generally given to the gray or brownish ground squirrels of the plains, classified as spermophiles by naturalists; and they are so varied, numerous and destructive wherever grain is grown, from the prairies of Kansas and Nebraska to the California valleys, and northward to the Saskatchewan, that extensive and costly poisoning operations are necessary to suppress them. Similar to them, but larger, are the prairie dogs, whose communities, or towns, of burrows and tunnels render useless large tracts of land in the southern half of the plains. Very similar animals to these abound in Russia and eastward throughout the open country of central Asia. They have undoubtedly increased much within late years through the killing off of the natural enemies that in the old days held their multiplication in check.
The prairie dogs used to be called "marmots," a term that applies more properly to some larger European burrowing rodents and to our woodchucks, which are so common all over the eastern half of the country, and, in another species, on the summits of the northern Rockies, where they are known as "whistlers." The most remarkable thing about them is the length and intensity of their dormancy in hibernation. There remains only the beaver, the largest of the rodents except the capybara, and altogether the most important one, measured by the value of its fur, and by the service its race has done through thousands of years in preparing, by its clearings and dams, valleys for man's cultivation.
Every beaver settlement is a true colony, the offspring of some previous settlement, which may be hundreds of years old. When such a settlement becomes too populous for the food supply, young males and their mates travel to some fresh spot by a small woodland stream, and begin life by digging a burrow in the bank with an underwater entrance, and at once dam up the stream by piling sticks, sod and mud across its current at some favorable spot below their home, the effect, if not the conscious purpose, of which is to maintain a depth of water in the stream at all seasons sufficient to cover the entrance to the burrow, and also to permit the storage of green wood under water (and ice) near the home for food (they eat the bark) during the next winter. The young beavers born that season will remain through the winter with the parents, and a domelike house is usually built in which the family lives. Next season the young set up a home for themselves near by, and so the colony grows. Beavers get most of their food by cutting down trees other than evergreens, and gnawing the bark. As the trees disappear near the bank, and the colony increases, the dam is enlarged so as to spread the set-back water over a wider territory; and later canals are cut deep into the woods, permitting far-away trees to be felled, and their pieces floated to the houses, especially in gathering the supply for winter. Old dams are sometimes 100 or more yards long, and are built with astonishing intelligence with reference to holding back a great breadth of water. These are diligently and skillfully repaired; and the houses become, in the course of years, big enough to accommodate three generations of beavers at once, and are so massive, especially when frozen in winter, which is the time of most danger from their enemies, that they are practically safe from attack. From such a mature colony others are continually formed, until in a level, swampy region the whole district is well occupied by beavers. This is possible now, of course, only in the remote Northwest; but a few beavers survive in the Rocky Mountain region of the United States, under protective laws, and they are still numerous in the more thinly settled parts of Canada, and furnish a large return to trappers.
[CHAPTER XXIX]
MAMMALS OF THE SEA
Whale is a general name for the extensive and varied order of marine mammals termed in science Cetacea. Their origin is obscure, but it is certain that their very ancient ancestors were land animals, evidence of which is afforded by their anatomy, especially in embryonic and very young specimens. Here are classified not only the great true whales but their smaller relatives, the sportive dolphins and porpoises, the grampuses or blackfish, the white whales often seen in the lower St. Lawrence River, the killers, and such out-of-the-way forms as the narwhal, from whose snout projects a long twisted "tusk," which is a strangely overgrown incisor tooth. In all these animals the shape is fishlike, as is required by the fishlike habits; the skin is smooth and usually blackish, or black with white markings; the forelimbs have become paddles and the tail a pair of horizontal flukes. As they are mammals with lungs and breathe air, whales must come to the surface frequently for that purpose. At the instant they emerge the pent-up air is expelled from the lungs through the nostrils at the top of the nose. In the case of the larger species this big discharge of moist breath condenses in the cold air into a visible vapor, often mixed with sea spray, which is called a "blowing"; but no water is expelled from the mouth, with which the "blowholes" have no connection. The smaller kinds of cetaceans, of which the variety is immense, are in the main fish-eaters, but the killer seizes and devours porpoises and seals also, and a band of them may unite to worry a big cachalot to death. Most species go about in small bands, or "schools."
The great whales are of two distinct families: (1) baleen whales, and (2) toothed whales. The first take their name from the blade-shaped plates of horny material (whalebone) hanging, to the number of two or three hundred, from the roof of the mouth, each central blade eight or ten feet long in ordinary cases. These "right" (i. e., proper) whales, as they are called by the men who hunt for and harpoon them, are huge creatures often fifty to seventy-five feet long, ranging all northern oceans, even amid arctic ice; yet, despite their bulk, they feed exclusively on the small crustaceans and other minute creatures of the plankton swept into the mouth by the million as the whale rushes along the surface, the water scooped up escaping from the sides of the mouth, and the food being caught by the fringes of baleen and swallowed like a continuous meal. In addition to the whalebone obtained from these whales the hunters cut away and save the thick layer of fat (blubber) under the skin for the sake of the oil it yields. The beeflike flesh of the muscles is good meat. This kind of whale is becoming very scarce.
The toothed whales consist of the single species called sperm whale, or "cachalot," which is of gigantic size, a lesser cousin ("kogia"), and an inferior genus, the beaked whales of the Antarctic. All are more common in the tropics and South Pacific than elsewhere. The great sperm whale differs in form from a "right" one mainly in having a huge, flattopped, almost square-fronted head, beneath which is hinged a somewhat shorter underjaw. The cavernous mouth is armed with strong, pointed teeth, and these whales prey on fish and especially on cuttlefish. They can swallow whole nothing larger than a salmon, but can bite larger prey into manageable pieces, and have more than once seized and crushed a boat in their jaws. The cachalot attacks the giant squid whenever it meets one and the marks of the squid's winding arms and cruel suckers are often seen on the hides of whales as scars of some struggle between these Titans of the deep. The value to mankind of the sperm whale lies in the liquid fat and the valuable substance, spermaceti, that fill a vast cavity in the top of its skull, a single whale yielding several barrels of it, from which the commercial "spermaceti" and a fine oil are extracted. In their intestines are frequently found lumps of the secretion known as "ambergris," used as a base for perfumes, the price of which is so high in the market that a few pounds will cover the expenses of a ship's voyage. Ambergris is also found floating in the open sea or cast up on shore, and for a long time its origin was unknown.
[CHAPTER XXX]
THE WORLD'S HERDS AND FLOCKS
The great tribe of animals called Ungulata ("hoofed") or Herbivora (eaters of herbage—herbivores), combines two types of structure into which they have diverged since their origin at the dawn of the Tertiary era, namely:
I. Odd-toed, or solid-hoofed, ungulates (Perissodactyla), typified by horses; and
II. Even-toed, or split-hoofed, ungulates (Artiodactyla), typified by the cattle.
They exist in every part of the habitable globe except Australasia, have furnished sustenance to the larger Carnivora, and have supplied the need of man for assistance in his labor, and with materials for food, shelter, and clothing. Without them modern civilization would have been impossible.
Both divisions have lost the plantigrade (flat-soled) walk of their early ancestors, and now step on the tips of their toes. This has been gradually gained as an adaptation to the increase of dry land and the formation of grassy plains, which we know went on steadily, especially through the last third of the Tertiary era. The short, massive legs and spreading, five-toed feet, useful in sustaining an animal's weight in marshes, were slowly changed to longer, more slender limbs and a digitigrade walk as greater speed and nimbleness were required in making their way over wide pastures to and from watering places or in escaping the beasts of prey, which were themselves becoming swifter and more active in jumping by a coordinate evolution of abilities. But before proceeding to the typical hoofed tribes, mention must be made of the elephants, which belong in this order. Elephants appear to stand apart from all other mammals, and from the earliest times have attracted attention by their huge bulk and strength, and by traditions of their intelligent performances. They seem a necessary part of our ideas of Oriental life and grandeur, and a circus without trick elephants would be a poor show in the eyes of the American youngster.
| THE SOUTHERN MAMMOTH |
| Drawn by Christman. (American Museum of Natural History) |
The naturalist classifies them (order Proboscidea) in this place because they are plainly, although remotely, related in structure to the solid-hoofed browsers; but only recently has he been able to trace their ancestry back to a small, tapirlike forefather of Miocene days, with no trunk and no tusks. The trunk, of course, is the animal's lengthened nose, become an organ useful for many purposes other than breathing; and the tusks are overgrown upper incisor teeth. The elephants of the present time are few compared with those of warmer past ages, when many species, as well as various cousins, such as long-haired mammoths and towering mastodons, wandered over Europe, Asia, and our own country. Now only two kinds remain: one in Africa, the other Asiatic. They differ in many ways, most noticeably in the size of the ears, which in the African elephant are very much larger than those of the Asiatic species. Both are forest animals, feeding on leaves and twigs. African elephants were formerly to be found all over the wooded parts of that continent, traveling about in herds that sometimes numbered a hundred or more individuals; and were varied in appearance, some being taller than any Oriental one, while others (in the Congo region) are so small as to be called dwarfs. The natives have never captured and made use of them, and few have been tamed by anyone within recent years, but in the time of the Carthaginians and Romans they were held captive, ridden, and employed in war, and in sports of the arena. They have been greatly reduced in numbers by ivory hunters, and would be nearly or quite extinct now had they not been protected in recent years by wise laws.
The Asiatic, or "Indian" elephant, which is confined to India, Ceylon, Burma, and the Malay countries, still roams the jungles as a wild animal, but every herd is known to and protected by the local governments, and from time to time these are rounded up, and young ones are captured and trained to man's service. Only in this way can the domestic supply be maintained, since these elephants rarely produce young when in captivity. They are utilized as riding and burden-bearing beasts, for hauling heavy loads, especially in the army service, and in handling large timber and other industrial operations. Some ivory is obtained from this species, but the tusks are far smaller than those of the African elephants, and the females bear none at all, while both sexes are armed in Africa, where an old "bull's" tusks have been known to exceed a weight of 300 pounds each.
| PREHISTORIC STRAIGHT-TUSKED ELEPHANT |
| Drawn by Christman. (American Museum of Natural History) |
Although there is no reason to suppose the African elephant is less intelligent by nature than the Oriental one, nearly all the evidence of thoughtfulness in these animals comes from Indian examples—a species that has been studied and educated for hundreds of years. That they may be taught to do almost anything of which their bodies are capable is plain; but undoubtedly they comprehend very largely the purposes of the man directing them, and use "brains" in assisting him to carry them out. They have retentive memories, appreciate kindness, and constantly show skill and discretion in accomplishing what they are asked to do. In regard to no other sort of animal has so much been written as of elephants; and the sum of the testimony is that they are not only very teachable and faithful in performing their tasks, when not disabled by fear, but often use surprisingly good judgment in their work.
Distantly related to the elephants, yet so remote in relationship to anything else as to be set apart in an order (Hyracoidea) by themselves, and with no visible geological ancestry, are the queer little "conies" of the Scriptures, called rock rabbits, and dassies in South Africa. They have a singular resemblance to rabbits, apart from their little round ears, and are more like enlarged copies of our western pikas, but their anatomy and teeth show they are far from being rodents; and they are classified here mainly by reason of their rhinoceroslike teeth, and the hooflets on their toes, so that they form a quaint intermediary between the elephants and the solid-hoofed section of the ungulates; they are, indeed, relics of an exceedingly primitive and ancestral type of ungulates.