by Aristotle
[486b5] Among them, most of the parts as a rule exhibit differences through contrariety of properties, such as colour and shape, in that some are more and some in a less degree the subject of the same property; and also in the way of multitude or fewness, magnitude or smallness, in short in the way of excess or defect. Thus in [10] some the texture of the flesh is soft, in others firm; some have a long bill, others a short one; some have abundance of feathers, others have only a small quantity. It happens further that, even in the cases we are considering, some have parts that others have not: for instance, some have spurs and others not, some have crests and others not; but as a general rule, most parts and those that go to make up the bulk of the body are either identical with one another, or differ from one another in the way [15] of contrariety and of excess and defect. For the more and the less may be represented as excess and defect.
There are some animals whose parts are neither identical in form nor differing in the way of excess or defect; but they are the same only in the way of analogy, as, for instance, bone is only analogous to fish-bone, nail to hoof, hand to claw, and [20] scale to feather; for what the feather is in a bird, the scale is in a fish.
The parts, then, which animals severally possess are diverse from, or identical with, one another in the fashion above described. And they are so furthermore in the way of local disposition; for many animals have identical parts that differ in position; for instance, some have teats in the breast, others close to the thighs. [487a1]
Of the substances that are composed of parts uniform with themselves, some are soft and moist, others are dry and solid. The moist are such either absolutely or so long as they are in their natural conditions, as, for instance, blood, serum, lard, suet, marrow, sperm, gall, milk in such as have it, flesh and the like; and also, in a different way, the waste products, as phlegm and the excretions of the belly and the [5] bladder. The dry and solid are such as sinew, skin, vein, hair, bone, gristle, nail, horn (a term which as applied to the part involves an ambiguity, when the whole also by virtue of its form is designated horn),1 and such parts as present an analogy to these. [10]
Animals differ from one another in their modes of subsistence, in their actions, in their habits, and in their parts. Concerning these differences we shall first speak in broad and general terms, and subsequently we shall treat of the same with close reference to each particular genus.
Differences are manifested in modes of subsistence, in habits, and in actions as follows: some animals live in water and others on land. And of those that live in [15] water some do so in one way, and some in another: that is to say, some live and feed in the water, take in and emit water, and cannot live if deprived of water, as is the case with the great majority of fishes; others get their food and spend their days in [20] the water, but do not take in water but air, nor do they bring forth in the water. Many of these creatures are furnished with feet, as the otter, the beaver, and the crocodile; some are furnished with wings, as the diver and the grebe; some are destitute of feet, as the water-snake. Some creatures get their living in the water and cannot exist outside it: but for all that do not take in either air or water, as, for [25] instance, the sea-anemone and the oyster. And of creatures that live in the water some live in the sea, some in rivers, some in lakes, and some in marshes, as the frog and the newt.
Of animals that live on land some take in air and emit it, which phenomena are termed inhalation’ and ‘exhalation’; as, for instance, man and all such land animals [30] as are furnished with lungs. Others, again, do not inhale air, yet live and find their sustenance on dry land; as, for instance, the wasp, the bee, and all other insects. And by insects I mean such creatures as have notches on their bodies, either on their bellies or on both backs and bellies.
[487b1] And of land animals many, as has been said, derive their subsistence from the water; but of creatures that live in and inhale water none derives its subsistence from the land.
Some animals at first live in water, and by and by change their shape and live [5] out of water, as is the case with river worms—for out of these the gadfly develops.2
Furthermore, some animals are stationary, and some move about. Stationary animals are found in water, but no such creature is found on land. In the water are many creatures that live in close adhesion to an external object, as is the case with [10] several kinds of shellfish. (The sponge actually appears to be endowed with a certain sensibility: as a sign of which it is alleged that the difficulty in detaching it is increased if the movement is not covertly applied.)
Other creatures adhere at one time to an object and detach themselves from it at other times, as is the case with a species of the so-called sea-anemone; for some of these creatures seek their food in the night-time loose and unattached.
Many creatures are unattached but motionless, as is the case with oysters and [15] the so-called holothuria. Some can swim, as, for instance, fishes, molluscs, and crustaceans, such as the crayfish. But some move by walking, as the crab, for it is the nature of the creature, though it lives in water, to move by walking.
Of land animals some are furnished with wings, such as birds and bees, and these are so furnished in different ways one from another; others are furnished with [20] feet. Of the animals that are furnished with feet some walk, some creep, and some wriggle. But no creature is able only to move by flying, as the fish is able only to swim; for the animals with leathern wings can walk, the bat has feet, and the seal has imperfect feet.
Some birds have feet of little power, and are therefore called apodes.3 This [25] little bird is powerful on the wing; and, as a rule, birds that resemble it are weak-footed and strong-winged, such as the swallow and the swift; for all these birds resemble one another in their habits and in their wings and look like one another. (The apous is to be seen at all seasons, but the swift only after rainy [30] weather in summer; for this is the time when it is seen and captured, though, as a general rule, it is a rare bird.)
Again, many animals move by walking as well as by swimming.
Furthermore, the following differences are manifest in their modes of living and in their actions. Some are gregarious, some are solitary, whether they be [488a1] furnished with feet or wings or be fitted for a life in the water; and some partake of both characters. And of the gregarious, some are social, others independent.
Gregarious creatures are, among birds, such as the pigeon, the crane, and the swan (no bird furnished with crooked talons is gregarious). Of creatures that live in [5] water many kinds of fishes are gregarious, such as the so-called migrants, the tunny, the pelamys, and the bonito.
Man partakes of both characters.
Social creatures are such as have some one common object in view; and this property is not common to all creatures that are gregarious. Such social creatures are man, the bee, the wasp, the ant, and the crane. [10]
Again, of these social creatures some submit to a ruler, others are subject to no rule: as, for instance, the crane and the several sorts of bee submit to a ruler, whereas ants and numerous other creatures are subject to no rule.
And again, both of gregarious and of solitary animals, some are attached to a fixed home and others are nomadic.
Also, some are carnivorous, some graminivorous, some omnivorous: whilst [15] some feed on a peculiar diet, as for instance the bees and the spiders (for the bee lives on honey and certain other sweets, and the spider lives by catching flies); and some creatures live on fish. Again, some creatures catch their food, others treasure it up, whereas others do not.
Some creatures provide themselves with a dwelling, others go without one: of [20] the former kind are the mole, the mouse, the ant, the bee; of the latter kind are many insects and quadrupeds. Further, in respect to locality of dwelling-place, some creatures dwell under ground, as the lizard and the snake; others live on the surface of the ground, as the horse and the dog. Some make themselves holes, others do not do so.4
Some are nocturnal, as the owl and the bat; ot
hers live in the daylight. [25]
Moreover, some creatures are tame and some are wild: some are at all times tame, as the jennet and the mule; others are at all times wild, as the leopard and the wolf; and some creatures can be rapidly tamed, as the elephant.
Again, we may regard animals in another light. For, whenever a race of animals is found domesticated, the same is always to be found in a wild condition; as we find to be the case with horses, cattle, pigs, donkeys,5 sheep, goats, and dogs. [30]
Further, some animals emit sound while others are mute, and some are endowed with voice: of these latter some have articulate speech, while others are inarticulate; some are noisy, some are prone to silence; some are musical, and some unmusical; but all animals without exception exercise their power of singing or chattering chiefly in connexion with the intercourse of the sexes. [488b1]
Again, some creatures live in the fields, as the cushat; some on the mountains, as the hoopoe; some frequent the abodes of men, as the pigeon.
Some, again, are peculiarly salacious, as the partridge and the cockerel; others are inclined to chastity, as the whole tribe of crows, for birds of this kind indulge but [5] rarely in sexual intercourse.
Of marine animals, again, some live in the open seas, some near the shore, some on rocks.
Furthermore, some are combative, others defensive. Of the former kind are such as act as aggressors upon others or retaliate when subjected to ill usage, and of the latter kind are such as have some means of guarding themselves against [10] attack.
Animals also differ from one another in regard to character in the following respects. Some are good-tempered, sluggish, and not prone to ferocity, as the ox; [15] others are quick-tempered, ferocious and unteachable, as the wild boar; some are intelligent and timid, as the stag and the hare;6 others are mean and treacherous, as the snake; others are free and courageous and high-bred, as the lion; others are thorough-bred and wild and treacherous, as the wolf. (An animal is high-bred if it come from a good stock, and an animal is thorough-bred if it does not deflect from its natural characteristics.)
[20] Further, some are crafty and mischievous, as the fox; some are spirited and affectionate and fawning, as the dog; others are easy-tempered and easily domesticated, as the elephant; others are cautious and watchful, as the goose; others are jealous and self-conceited, as the peacock. But of all animals man alone is capable of deliberation.
[25] Many animals have memory, and are capable of instruction; but no other creature except man can recall the past at will.
With regard to the several genera of animals, particulars as to their characters and ways of life will be discussed more precisely later on.
2 · Common to all animals are the parts by which and the parts into which [30] they take food; and these are either identical with one another, or are diverse in the ways above specified: to wit, either identical in form, or varying in respect of excess or defect, or resembling one another analogically, or differing in position.
Furthermore, the great majority of animals have other parts besides these in common, whereby they discharge the residuum of their food—but this is not true of [489a1] all. The part by which food is taken in is called the mouth, and the part into which it is taken, the belly; the remainder has a great variety of names.
Now the residuum of food is twofold in kind and such creatures as have parts receptive of wet residuum are found with parts receptive of dry residuum too; but [5] such as have the latter do not all have the former. That is why an animal has a belly if it has a bladder; but those that have a belly do not all have a bladder. For the part receptive of wet residuum is termed ‘bladder’, and that of dry residuum ‘belly’.
3 · Of the rest, a great many have, besides the parts above-mentioned, a part [10] for the emission of the sperm; and of animals capable of generation one emits into another, and the other into itself. The latter is termed ‘female’, and the former ‘male’; but some animals have neither male nor female. Consequently, the parts connected with this function differ in form; for some animals have a womb and others an organ analogous thereto.
The above-mentioned parts, then, are the most indispensable for animals; and [15] with some of them all animals, and with others animals for the most part, are provided.
One sense, and one alone, is common to all animals—the sense of touch. Consequently, there is no special name for the part in which it has its seat; for in some groups of animals it is identical, in others it is analogous.
4 · Every animal is supplied with moisture, and if the animal be deprived of [20] the same by natural causes or by violence, death ensues; further, every animal has another part in which the moisture is contained. These parts are blood and vein, and in other animals there is something to correspond; but in these latter the parts are imperfect, being fibre and serum.
Touch has its seat in a part uniform with itself as in the flesh or something of the kind, and generally, with animals supplied with blood, in the parts charged with [25] blood. In other animals it has its seat in parts analogous to the parts charged with blood; but in all cases it is seated in parts that are uniform with themselves.
The active faculties, on the contrary, are seated in the parts that are not uniform: as, for instance, the business of preparing the food is seated in the mouth, and the office of locomotion in the feet, the wings, or in organs to correspond.
Again, some animals are supplied with blood, as man, the horse, and all [30] such animals as are, when full-grown, either destitute of feet, or two-footed, or four-footed; other animals are bloodless, such as the bee and the wasp, and, of marine animals, the cuttle-fish, the crayfish, and all such animals as have more than four feet.
5 · Again, some animals are viviparous, others oviparous, other vermiparous. Some are viviparous, such as man, the horse, the seal, and all other animals that are [489b1] hair-coated, and, of marine animals, the cetaceans, as the dolphin, and the so-called selachia. (Of these latter animals, some have a tubular air-passage and no gills, as the dolphin and the whale: the dolphin with the air-passage going through its back, [5] the whale with the air-passage in its forehead; others have uncovered gills, as the selachia, the sharks and rays.)
What we term an egg is a certain completed result of conception out of which the animal that is to be develops—from a part of it at first, while the rest serves for food as it develops. A grub on the other hand is a thing out of which in its entirety the animal in its entirety develops, by differentiation and growth of the embryo. [10]
Of viviparous animals, some hatch eggs in their own interior, as the selachia; others engender in their interior, as man and the horse. When the result of conception is perfected, with some animals a living creature is brought forth, with others an egg is brought to light, with others a grub. Of the eggs, some have egg-shells and are of two different colours, such as birds’ eggs; others are [15] soft-skinned and of uniform colour, as the eggs of the selachia. Of the grubs, some are from the first capable of movement, others are motionless. However, with regard to these phenomena we must speak precisely hereafter when we come to treat of generation.
Furthermore, some animals have feet and some do not. Of such as have feet, some animals have two, as is the case with men and birds only; some have four, as [20] the lizard and the dog; some have more, as the centipede and the bee; but all have an even number of feet.
Of swimming creatures that are destitute of feet, some have fins, as fishes: and of these some have four fins, two above on the back, two below on the belly, as the [25] gilt-head and the basse; some have two only,—to wit, such as are exceedingly long and smooth, as the eel and the conger; some have none at all, as the muraena and others that use the sea just as snakes use dry ground—and snakes swim in water in [30] just the same way. Of the selachia some have no fins, such as those that are flat and long-tailed, as the ray and the sting-ray, but these fishes swim actually by means of their flat bodies; the fishing-frog however, has fins, and so likewise have all such
fishes as have not their flat surfaces thinned off to a sharp edge.
Of those swimming creatures that appear to have feet, as is the case with the molluscs, these creatures swim by the aid of their feet and their fins as well, and they swim most rapidly backwards in the direction of the trunk, as is the case with [490a1] the cuttle-fish and the calamary; but neither of these latter can walk as the octopus can.
The hard-skinned animals, like the crayfish, swim by their tail-parts; and they swim most rapidly tail foremost, by the aid of the fins developed upon that member. The newt swims by means of its feet and tail; and its tail resembles that of the [5] sheat-fish, to compare little with great.
Of animals that can fly some are furnished with feathered wings, as the eagle and the hawk; some are furnished with membranous wings, as the bee and the cockchafer; others are furnished with leathern wings, as the flying fox and the bat. Those possessed of blood have feathered wings or leathern wings; the bloodless [10] creatures have membranous wings, as insects. The creatures that have feathered wings or leathern wings all have either two feet or no feet at all:7 for there are said to be certain flying serpents in Ethiopia of this sort.
Creatures that have feathered wings are classed as a genus under the name of ‘bird’; the other two genera have no single name.
Of creatures that can fly and are bloodless some are coleopterous; for they [15] have their wings in a sheath or shard, like the cockchafer and the dung beetle; others are sheathless, and of these latter some are dipterous and some tetrapterous: tetrapterous, such as are large or have their stings in the tail, dipterous, such as are small or have their stings in front. The coleoptera are, without exception, devoid of [20] stings; the diptera have the sting in front, as the fly, the horsefly, the gadfly, and the gnat.