Chapter XXIX

).

The feeding and domestic habits and the whole general behavior of animals are extremely interesting subjects of observation and study. And such observation intelligently pursued will be of much value. The point to be kept ever in mind is that all animal habits are connected with certain conditions of life; that in every case there is an answer to the question "why." This answer may not be found; in many cases it is extremely difficult to get at, but often it is simple and obvious and can be found by the veriest beginner.

=Classification.=--The mammals of North America represent eight orders. Three additional mammalian orders, namely, the Monotremata, including the extraordinary duck-bills (_Ornithorhynchus_) and a species of _Tachyglossus_ in Australia and Tasmania; the Edentata, including the sloths, armadillos, and ant-eaters found in tropical regions; and the Sirenia, including the marine manatees and dugongs, are not represented (except by a single manatee) in North America. In the following paragraphs some of the more familiar mammals representing each of the eight orders represented in North America are referred to.

=The opossums (Marsupialia).=--The opossum (_Didelphys virginiana_) is the only North American representative of the order Marsupialia, the other members of which are limited exclusively to Australia and certain neighboring islands. The kangaroos are the best known of the foreign marsupials. After birth the young are transferred to an external pouch, the marsupium, on the ventral surface of the mother, in which they are carried about and fed. The opossum lives in trees, is about the size of a common cat, and has a dirty-yellowish woolly fur. Its tail is long and scaly, like a rat's. Its food consists chiefly of insects, although small reptiles, birds, and bird's eggs are eaten. When ready to bear young the opossum makes a nest of dried grass in the hollow of a tree, and produces about thirteen very small (half an inch long) helpless creatures. These are then placed by the mother in her pouch. Here they remain until two months or more after birth. Probably all the North American opossums found from New York to California and especially common in the Southern States belong to a single species, but there is much variety among the individuals.

=The rodents or gnawers (Glires).=--The rabbits, porcupines, gophers, chipmunks, beavers, squirrels, and rats and mice compose the largest order among the mammals. They are called the rodents or gnawers (Glires) because of their well-known gnawing powers and proclivities. The special arrangement and character of the teeth are characteristic of this order. There are no canines, a toothless space being left between the incisors and molars on each side. There are only two incisor teeth in each jaw (rarely four in the upper jaw), and these teeth grow continuously and are kept sharp and of uniform length by the gnawing on hard substances and the constant rubbing on each other. The food of rodents is chiefly vegetable.

Of the hares and rabbits the cottontail (_Lepus nuttalii_) and the common jack-rabbit (_L. campestris_) are the best known. The cottontail is found all over the United States, but shows some variation in the different regions. There are several species of jack-rabbits, all limited to the plains and mountain regions west of the Mississippi River. The food of rabbits is strictly vegetable, consisting of succulent roots, branches, or leaves. Rabbits are very prolific and yearly rear from three to six broods of from three to six young each. There are two North American species of porcupines, an Eastern one, _Erethizon dorsatus_, and a Western one, _E. epixanthus_. The quills in both these species are short, being only an inch or two in length, and are barbed. In some foreign porcupines they are a foot long. They are loosely attached in the skin and may be readily pulled out, but they cannot be shot out by the porcupine, as is popularly told. The little guinea-pigs (_Cavia_), kept as pets, are South American animals related to the porcupines.

The pocket gophers, of which there are several species mostly inhabiting the central plains, are rodents found only in North America. They all live underground, making extensive galleries and feeding chiefly on bulbous roots. The mice and rats constitute a large family of which the house-mice and rats, the various field-mice, the wood-rat (_Neotoma pennsylvanica_) and the muskrat (_Fiber zibethicus_) are familiar representatives. The common brown rat (_Mus decumanus_) was introduced into this country from Europe about 1775, and has now nearly wholly supplanted the black rat (_M. rattus_), also a European species, introduced about 1544. The beaver (_Castor canadensis_) is the largest rodent. It seems to be doomed to extermination through the relentless hunting of it for its fur. The woodchuck or ground-hog (_Arctomys monax_) is another familiar rodent larger than most members of the order. The chipmunks and ground-squirrels are commonly known rodents found all over the country. They are the terrestrial members of the squirrel family, the best known arboreal members of which are the red squirrel (_Sciurus hudsonicus_), the fox-squirrel (_S. ludovicianus_), and the gray or black squirrel (_S. carolinensis_). The little flying squirrel (_Sciuropterus volans_) is abundant in the Eastern States.

=The shrews and moles (Insectivora).=--The shrews and moles are all small carnivorous animals, which, because of their size, confine their attacks chiefly to insects. The shrews are small and mouse-like; certain kinds of them lead a semi-aquatic life. There are nearly a score of species in North America. Of the moles, of which there are but few species, the common mole (_Scalops aquaticus_) is well known, while the star-nosed mole (_Condylura cristata_) is recognizable by the peculiar rosette of about twenty cartilaginous rays at the tip of its snout. Moles live underground and have the fore feet wide and shovel-like for digging. The European hedgehogs are members of this order.

=The bats (Chiroptera).=--The bats (fig. 153), order Chiroptera, differ from all other mammals in having the fore limbs modified for flight by the elongation of the forearms and especially of four of the fingers, all of which are connected by a thin leathery membrane which includes also the hind feet and usually the tail. Bats are chiefly nocturnal, hanging head downward by their hind claws in caves, hollow trees, or dark rooms through the day. They feed chiefly on insects, although some foreign kinds live on fruits. There are a dozen or more species of bats in North America, the most abundant kinds in the Eastern States being the little brown bat (_Myotis subulatus_), about three inches long with small fox-like face, high slender ears, and a uniform dull olive-brown color, and the red bat (_Lasiurus borealis_), nearly four inches long, covered with long, silky, reddish-brown fur, mostly white at tips of the hairs.

[Illustration: FIG. 153.--The hoary bat, _Lasiurus cinereus_. (Photograph from life by J. O. Snyder.)]

=The dolphins, porpoises, and whales (Cete).=--The dolphins, porpoises, and whales (Cete) compose an order of more or less fish-like aquatic mammals, among which are the largest of living animals. In all the posterior limbs are wanting, and the fore limbs are developed as broad flattened paddles without distinct fingers or nails. The tail ends in a broad horizontal fin or paddle. The Cete are all predaceous, fish, pelagic crustaceans, and especially squids and cuttlefishes forming their principal food. Most of the species are gregarious, the individuals swimming together in "schools." The dolphins and porpoises compose a family (Delphinidæ) including the smaller and many of the most active and voracious of the Cete. The whales compose two families, the sperm-whales (Physeteridæ) with numerous teeth (in the lower jaw only) and the whalebone whales (Balænidæ) without teeth, their place being taken in the upper jaw by an array of parallel plates with fringed edges known as "whalebone." The great sperm-whales or cachalots (_Physeter macrocephalus_) found in southern oceans reach a length (males) of eighty feet, of which the head forms nearly one-third. Of the whalebone whales, the sulphur-bottom (_Balænoptera sulfurea_) of the Pacific Ocean, reaching a length of nearly one hundred feet, is the largest, and hence the largest of all living animals. The common large whale of the Eastern coast and North Atlantic is the right whale (_Balæna glacialis_); a near relative is the great bowhead (_B. mysticetus_) of the Arctic seas, the most valuable of all whales to man. Whales are hunted for their whalebone and the oil yielded by their fat or blubber. The story of whale-fishing is an extremely interesting one, the great size and strength of the "game" making the "fishing" a hazardous business.

[Illustration: FIG. 154.--Male elk or wapiti, _Cervus canadensis_. (Photograph by E. Willis from specimen mounted by Prof. L. L. Dyche, University of Kansas.)]

[Illustration: FIG. 155.--Antelope, male, female, and young, _Antilocapra americana_. (Photograph by E. Willis from specimens mounted by Prof. L. L. Dyche, University of Kansas.)]

=The hoofed mammals (Ungulata).=--The order Ungulata includes some of the most familiar mammal forms. Most of the domestic animals, as the horse, cow, hog, sheep, and goat, belong to this order, as well as the familiar deer, antelope, and buffalo of our own land and the elephant, rhinoceros, hippopotamus, giraffe, camel, zebra, etc., familiar in zoological gardens and menageries. The order is a large one, its members being characterized by the presence of from one to four hooves, which are the enlarged and thickened claws of the toes. The Ungulates are all herbivorous, and have their molar teeth fitted for grinding, the canines being absent or small. The order is divided into the Perissodactyla or odd-toed forms, like the horse, zebra, tapir, and rhinocerus, and the Artiodactyla or even-toed forms, like the oxen, sheep, deer, camels, pigs, and hippopotami. The Artiodactyls comprise two groups, the Ruminants and Non-ruminants. All of the native Ungulata of our Northern States belong to the Ruminants, so called because of their habit of chewing a cud. A ruminant first presses its food into a ball, swallows it into a particular one of the divisions of its four-chambered stomach, and later regurgitates it into the mouth, thoroughly masticates it, and swallows it again, but into another stomach-chamber. From this it passes through the other two into the intestine.

The deer family (Cervidæ) comprises the familiar Virginia or red deer (_Odocoileus americanus_) of the Eastern and Central States and the white-tailed, black-tailed, and mule deers of the West, the great-antlered elk or wapiti (_Cervus canadensis_) (fig. 154), the great moose (_Alce americana_) (fig. 152), largest of the deer family, and the American reindeer or caribou (_Rangifer caribou_). All species of the Cervidæ have solid horns, more or less branched, which are shed annually. Only the males (except with the reindeer) have horns. The antelope (_Antilocapra americana_) (fig. 155) common on the Western plains also sheds its horns, which, however, are not solid and do not break off at the base as in the deer, but are composed of an inner bony core and an outer horny sheath, the outer sheath only being shed. The family Bovidæ includes the once abundant buffalo or bison (_Bison bison_) (frontispiece), the big-horn or Rocky Mountain sheep (_Ovis canadensis_) (fig. 151), and the strange pure-white Rocky Mountain goat (_Oreamnos montanus_). The buffalo was once abundant on the Western plains, travelling in enormous herds. But so relentlessly has this fine animal been hunted for its skin and flesh that it is now practically exterminated (fig. 156). A small herd is still to be found in Yellowstone Park, and a few individuals live in parks and zoological gardens. In all of the Bovidæ the horns are simple, hollow, and permanent, each enclosing a bony core.

=The carnivorous mammals (Feræ).=--The order Feræ includes all those mammals usually called the carnivora, such as the lions, tigers, cats, wolves, dogs, bears, panthers, foxes, weasels, seals, etc. All of them feed chiefly on animal substance and are predatory, pursuing and killing their prey. They are mostly fur-covered and many are hunted for their skin. They have never less than four toes, which are provided with strong claws that are frequently more or less retractile. The canine teeth are usually large, curved, and pointed.

[Illustration: FIG. 156.--A buffalo, _Bison bison_, killed for its skin and tongue, on the plains of Western Kansas thirty years ago. (Photograph by J. Lee Knight.)]

While most of the Feræ live on land, some are strictly aquatic. The true seals, fur-seals, sea-lions, and walruses comprise the aquatic forms, all being inhabitants of the ocean. The true seals, of which the common harbor seal (_Phoca vitulina_) is our most familiar representative, have the limbs so thoroughly modified for swimming that they are useless on land. The fur-seals, sea-lions, and walruses use the hind legs to scramble about on the rocks or beaches of the shore. The fur-seals (fig. 157) live gregariously in great rookeries on the Pribilof or Fur Seal Islands, and the Commander Islands in Bering Sea.

The bears are represented in our country by the widespread brown, black, or cinnamon bear (_Ursus americanus_) and the huge grizzly bear (_U. horribilis_) of the West. The great polar bear (_Thalarctos maritimus_) lives in arctic regions. The otters, skunks, badgers, wolverines, sables, minks, and weasels compose the family Mustelidæ, which includes most of the valuable fur-bearing animals. Some of the members of this family lead a semi-aquatic or even strictly aquatic life and have webbed feet. The wolves, foxes, and dogs belong to the family Canidæ. The coyote (_Canis latrans_), the gray wolf (_C. nubilus_), and the red fox (_Vulpes pennsylvanicus_) are the most familiar representatives of this family, in addition to the dog (_C. familiaris_), which is closely allied to the wolf. "Most carnivorous of the carnivora, formed to devour, with every offensive weapon specialized to its utmost, the Felidæ, whether large or small, are, relatively to their size, the fiercest, strongest, and most terrible of beasts." The Felidæ or cat family includes the lions, tigers, hyenas, leopards, jaguars, panthers, wildcats, and lynxes. In this country the most formidable of the Felidæ is the American panther or puma (_Felis concolor_). It reaches a length from nose to root of tail of over four feet. Its tail is long. The wildcat (_Lynx rufus_) is much smaller and has a short tail.

[Illustration: FIG. 157.--The Lukanin rookery of fur seals, _Callorhinus alascanus_, on St. Paul Island, Pribilof Group, Bering Sea. (Photograph from life by the Fur Seal Commission.)]

=The man-like mammals (Primates).=--The Primates, the highest order of mammals, includes the lemurs, monkeys, baboons, apes, and men. Man (_Homo sapiens_) is the only native representative of this order in our country. All the races and kinds of men known, although really showing much variety in appearance and body structure, are commonly included in one species. The chief structural characteristics which distinguish man from the other members of this order are the great development of his brain and the non-opposability of his great toe. Despite the similarity in general structure between him and the anthropoid apes of the Old World, in particular the chimpanzee and orang-outang, the disparity in size of brain is enormous.

[Illustration: FIG. 158.--"Bob Jordan," a monkey of the genus _Cercopithecus_. (Photograph from life by D. S. Jordan.)]

The lowest Primates are the lemurs found in Madagascar, in which island they include about one-half of all the mammalian species found there. The brain is much less developed in the lemurs than in any of the other monkeys. The monkeys and apes may be divided into two groups, the lower, platyrrhine monkeys, found in the New World, and the higher, catarrhine forms, limited to the Old World. The platyrrhine monkeys have wide noses in which the nostrils are separated by a broad septum and with the openings directed laterally. These monkeys are mostly smaller and weaker than the Old World forms and are always long-tailed, the tail being frequently prehensile. They include the howling, squirrel, spider, and capuchin monkeys common in the forests of tropical South America. The catarrhine monkeys have the nose-septum narrow and the openings of the nostrils directed forwards, and the tail is wanting in numerous members of the group. They include the baboons, gorillas, orang-outangs, and chimpanzees. These apes have a dentition approaching that of man, and in all ways are the animals which most nearly resemble man in physical character.

## PART III

ANIMAL ECOLOGY

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