A common misconception that exists today is that the lifespan of early humans was extremely short. Often people quote numbers like 30 years as the average life span of early hunter gatherers and farmers. A look at modern day hunter-gatherer societies is the best way to examine the likely life span of early humans.
The study longevity Among Hunter-Gatherers: A Cross cultural Examination covers this topic with a look at the human life span in several different cultures. The study puts forward the hypothesis that there is a prototypical pre-industrial mortality profile in humans. Or in other words, there is a normal human lifespan that can be seen across many cultures and levels of pre-industrial development.
Our conclusion is that there is a characteristic life span for our species, in which mortality decreases sharply from infancy through childhood, followed by a period in which mortality rates remain essentially constant to about age 40 years, after which mortality rises steadily in Gompertz fashion. The modal age of adult death is about seven decades, before which time humans remain vigorous producers, and after which senescence rapidly
occurs and people die.
We hypothesize that human bodies are designed to function well for about seven decades in the environment in which our species evolved. Mortality rates differ among populations and among periods,
especially in risks of violent death. However, those differences are small in a
comparative cross-species perspective, and the similarity in mortality proﬁles
of traditional peoples living in varying environments is impressive.
AVERAGE WORLDWIDE HUMAN life expectancy reached 66 years in the first quinquennium of the twenty-ﬁrst century, with extremes at the country level ranging from 39 years in Zambia to 82 years in Japan (United Nations 2007). Average life expectancy has increased linearly at almost three months
per year over the past 160 yearsAmong traditional hunter-gatherers, the average life expectancy at birth varies from 21 to 37 years
Infant mortality is over 30 times greater among hunter-gatherers, and early child mortality is over 100 times greater than encountered in the United States.we see that on average 57 percent, 64 percent, and 67 percent of children born survive to age 15 years among hunter-gatherers, forager-horticulturalists, and acculturated hunter-gatherers.
life expectancy at age 15 is 48 years for Aborigines, 52 and 51 for settled Ache and !Kung, yet 31 and 36 for peas-
ant and transitional Agta.Survival to age 45 varies between 19 and 54 percent, and those aged 45 live an average of 12–24 additional years