Omniana/Volume 2/Longevity
233. Longevity.
There is nothing in the system of nature which in our present state of knowledge appears so unintelligible as the scale of longevity. It must be admitted, indeed, that our knowledge upon this subject is very imperfect; but all that is known of domesticated animals, and the accidental facts which have been preserved concerning others, tend to the strange result, that longevity bears no relation either to strength, size, complexity of organization, or intellectual power. True it is that birds, which seem to rank higher than beasts in the scale of being, are also much longer lived. Thirty is a great age for a horse, dogs usually live only from fourteen years to twenty; but it is known that the goose and the hawk exceed a century. But fish, evidently a lower rank in creation than either, are longer lived than birds: it has been said of some species, and of certain snakes also, that they grow as long as they live, and as far as we know, live till some accident puts an end to their indefinite term of life. And the toad! it cannot indeed be said that the toad lives for ever, but many of these animals who were cased up at the general deluge, are likely to live till they are baked in their cells at the general conflagration.
I have said that birds seem to rank higher than beasts in the scale of being, because the ςοργη, which in beasts is confined to the female, extends in birds to both sexes; and because they have the connubial affection, to which there seems no nearer approach among beasts than the Turk-like polygamy of some of the gregarious species.