. . .se, none the less, frequently attain considerable ages, ducks having been known to live for 29 years. Even the common fowl, which is a notoriously prolific bird, may reach an age of twenty to thirty years.

It will be said, however, that these birds are exposed to many enemies during youth. Chickens, ducklings, and goslings are ready prey for hawks, foxes and small carnivora. The longevity is possibly to be explained as an adaptation for the preservation of the species by compensating for the great destruction of the young. Weismann explains in this way the longevity of many aquatic birds and other creatures that are much preyed on. It must be noted, however, that the longevity cannot depend on the risks run by the young birds, but must have arisen independently. If this had not occurred, creatures, the young of which are destroyed in great numbers, would have ceased to exist, as many species have disappeared in geological time. The longevity of prolific anima. . . Read More