Chapter XII.

1. Animals also differ in the age at which sexual intercourse commences. For in the first place the period at which the spermatic fluid begins to be secreted, and the age of puberty is not the same, but different; for the young of all animals are barren, or if they do possess the power of reproduction, their offspring are weak and small. This is very conspicuous in mankind, and in viviparous quadrupeds and birds, for in the one the offspring, in the other the eggs, are small. The age of puberty is nearly the same in the individuals of each kind, unless any alteration takes place, either as ominous, or from an injury done to their nature.

2. In men this period of life is shown by the change of voice, and not only by the size but by the form of the pudendum and of the breasts in women, but especially by the growth of hair on the pubes. The secretion of the spermatic fluid commences about the age of fourteen, the power of reproduction at twenty-one. Other animals have no hair on the pubes, for some have no hair at all, and others have none upon their under side, or less than on their upper side, but the change of the voice is conspicuous in some of them. And in others different parts of the body signify the period of the formation of the semen, and of the power of reproduction.

3. In almost all animals the voice of the female and of the young is more acute than that of the male and the older animals, for even the stags have a deeper voice than their females. The males utter their cry at the season of copulation, the females when they are alarmed. The voice of the female is short, that of the male longer. And the barking of old dogs is also deeper than of young ones, and the voice of the horse also varies. The females utter a little small cry as soon as they are born, and the males do the same, but their voice is deeper than that of the female, and as they grow older, it still increases. When they are two years old, and reach puberty, the male utters a great deep voice, that of the female is greater and clearer than it was at first; this continues till they are twenty years old at the outside, and after that the voice, both of the male and female, becomes weaker.

4. For the most part, then, as we observed, the voice of the male differs from that of the female in depth, in those animals which utter a lengthened sound. There are, however, some exceptions, as oxen; for in these animals the voice of the female is deeper than that of the male, and the voice of the calf than that of the full-grown animal; wherefore also in the castrated animals, the voice changes the other way, for it becomes more like that of the female.

5. The following are the ages at which animals acquire the power of reproduction. The sheep and goat arrive at puberty within a year after they are born, and especially the goat, and the males as well as the females, but the offspring of these males and of the others is different. For the males are better the second year than when they become older. In hogs, the male and female unite at eight months old, and the female produces her young when she is a year old, for this agrees with the period of gestation. The male reaches puberty at eight months old, but his offspring are useless till he is a year old. But these periods, as we have said, are not always the same, for swine will sometimes copulate when they are four months old, so as to have young and nurse them at six months old, and boars sometimes reach puberty at ten months old, and continue good to three years old.

6. The bitch reaches puberty within a year after birth, and so does the dog, and sometimes this takes place at the end of eight months, but more frequently in the male than in the female. The period of gestation is sixty days, or one or two, or perhaps three days more, but never less than sixty days, or if they produce young in a less time, it never comes to perfection. The bitch is ready for sexual intercourse again in six months, but never sooner. The horse reaches puberty in both sexes at two years old, and is capable of reproduction, but its offspring at that age are small and weakly. For the most part, sexual intercourse begins at three years of age, and the colts continue to improve from that period till they are twenty years old. The male is useful till he is thirty years old, so that he can beget during almost the whole of his life, for the horse generally lives five-and-thirty years, and the mare more than forty, and a horse has been known to live seventy-five years.

7. The ass reaches puberty in both sexes at the age of thirty months; they rarely, however, produce young till they are three years, or three years and six months old. But it has been known to be pregnant and bring up its young within the year. The cow also has been known to produce young and rear it within the year after birth, which grew to the ordinary size, and no more.[163]

8. These are the periods of puberty in these animals. The seventieth year in man, and the fiftieth in woman, is the latest period of reproduction, and this happens rarely, for only a few have had children at this time of life. Sixty-five is generally the boundary in one sex, and forty-five in the other. The sheep produces young till it is eight years old, and, if well treated, until it is eleven, though the act of copulation is continued in both sexes during the whole period of life.

9. Fat goats are rarely productive, wherefore they compare barren vines with barren goats, but they are productive when they are lean. The rams copulate with the old sheep first, but they do not follow after the younger; and the younger, as I before observed, produce a smaller offspring than the older.

10. A wild boar will beget till he is three years old, but the progeny of older animals is inferior; for he has not the same power or strength. He generally goes to the female when full of food, and without having been to another female, or, if not, the act of coition is of shorter duration, and the progeny smaller. The sow produces the smallest number of pigs at her first litter, but at the second they are more flourishing. She also produces young when old, but the act of coition is longer. At fifteen years old, she no longer produces young, but becomes fierce.

11. If well-fed, she will be more ready for sexual intercourse, whether young or old; and, if rapidly fattened when pregnant, she has less milk after parturition. As regards the age of the parent, the young of those in the prime of their age are the best, and those that are born at the beginning of winter. The worst are those born in the summer, for they are small, and thin, and weak. If the male is well fed, he is ready for sexual intercourse at all seasons, by day as well as by night; but if not well fed, he is most ready in the morning, and as he grows old, he becomes less disposed for it, as was said before. And it frequently happens that those which are impotent, through age or weakness, and cannot copulate readily, will approach the female as she lies down tired with long standing. The sow generally becomes pregnant when she hangs down her ears in her heats; if she is not pregnant, she becomes heated again.

12. Bitches do not copulate during the whole of their life, but only to a certain period. Their coition and pregnancy generally takes place till they are twelve years old, but both males and females have been known to perform the act of coition at eighteen and even twenty years of age; but old age takes away from both sexes the power of reproduction, as in other animals.

13. The camel is retroningent, and performs the act of intercourse in the manner already described; the period of its coition in Arabia is in the month of September; the female goes with young twelve months, and produces one foal, for the animal is one of those which produce but one. Both the male and female arrive at puberty at the age of three years, and the female is ready for the male again at the end of a year after parturition.

14. The elephant arrives at puberty, the earliest at ten years of age, the latest at fifteen, and the male at five or six years old. The season for the intercourse of the sexes is in the spring: and the male is ready again at the end of three years, but he never touches again a female whom he has once impregnated. Her period of gestation is two years, and then she produces one calf, for the elephant belongs to the class of animals which have but one young one at a time. The young one is as large as a calf of two or three months old. This, then, is the nature of the sexual intercourse of those animals which perform this function.