change their situation become more or less enduring than their
nature warrants, but never are they eternal when they contain contrary
qualities; for their matter is an immediate source of contrariety,
so that if it involves locality they show change of situation, if
quantity, increase and diminution, while if it involves qualitative
affection we find alteration of character.
4
We find that a superior immunity from decay attaches neither to
the largest animals (the horse has shorter life than man) nor to those
that are small (for most insects live but for a year). Nor are
plants as a whole less liable to perish than animals (many plants
are annuals), nor have sanguineous animals the pre-eminence (for the
bee is longer-lived than certain sanguineous animals). Neither is it
the bloodless animals that live longest (for molluscs live only a
year, though bloodless), nor terrestrial organisms (there are both
plants and terrestrial animals of which a single year is the
period), nor the occupants of the sea (for there we find the
crustaceans and the molluscs, which are short-lived).
Speaking generally, the longest-lived things occur among the plants,
e.g. the date-palm. Next in order we find them among the sanguineous
animals rather than among the bloodless, and among those with feet
rather than among the denizens of the water. Hence, taking these two
characters together, the longest-lived animals fall among
sanguineous animals which have feet, e.g. man and elephant. As a
matter of fact also it is a general rule that the larger live longer
than the smaller, for the other long-lived animals too happen to be of
a large size, as are also those I have mentioned.
5