Conservationists should remember that nature has wisely designed each
species of plant and animal with a built-in margin of safety; namely, a
surplus of young which will repopulate the species from periods of
extreme adversity. Yet these surpluses must somehow usually be
eliminated lest the species overpopulate its habitat and destroy its own
sustenance. The controls which limit the population are many and the
population existing from year to year is the statistical average of
these many controls. Diseases, predators, and other adversities are
necessary evils, which are in the final analysis blessings in disguise.
Whales, too, have their checks, although we are a long way from knowing
their relative importance.
Perhaps the most critical moment in the life of the whale is birth,
because the newborn whale must surface immediately or suffocate. Any
abnormality in the birth process or weakness on the part of the infant
may cause its loss. Inasmuch as a whale calves only every other year,
the loss of a baby is serious, and especially so because a whale
produces but a single calf. Less than one per cent of whale births are
twins which is about the same frequency as for humans. A careful
examination of the shores around the breeding lagoons reveals that a few
babies are lost at birth.