The paper shows it possible to use allometric equations to detect human and animal biological differences, including longevity. An actual man is shown to generally live 5 times longer than his allometric model constructed on the mean life longevity in mammals of different species from shrewmouse to elephant. The longer life of man is accounted for by his biosocial nature and by the influence of many socioeconomic factors. Therefore the mean longevity may serve as a universal integral index of the socioeconomic policy of some countries and regions. Critical considerations should be hold for the attempts to substitute the socioeconomic situation by the pure ecological one when outlining prospects of society development. Environmental protection programmes should not become an end in themselves, but they should be only a constituent of the general concept of development wherein priority is given to the socioeconomic problems of the population's life.