Nature appears to have distributed life spans, whether long or short, entirely upon the possession or non-possession of a few physiologically superficial characteristics, namely, immunity of mature, full-sized specimens from the effects of: (1) predation, (2) competition, (3) fire, (4) disease, and (5) the existence of a definite usefulness for long life spans in bridging lengthy periods unfavorable to the reproduction and/or maturation of offspring. Extremely strong correlations are presented in proof of the above relationships. Since longevity mechanisms can closely correlate to superficial traits, it is unlikely that they comprise an integral part of basic structural or biochemical processes. In the case of trees, all five of the above traits are apparently required for the achievement of potential life spans in excess of 1000 years. By contrast, the longest live animal species appear to fully possess only (1) and (3) of the five prerequisite traits above. This observation may fully account for the fact that maximum life spans of trees are 30-40 times greater than those of the longest lived animals.