Greg, I was wrong to quote such a person, but the stats. referred to are respectable and genuine.

See this source.
"To help gain an answer to this question, scientists have compared the life span of adults in contemporary hunter-gat once infant mortality rates were removed, life span was calculated to between 70 and 80 years, the same rate as that found in contemporary industrialised societies. - See more at: http://www.ancient-origins.net/news-evolution-human-origins/life-expectancy-myth-and-why-many-ancient-humans-lived-long-077889#sthash.0Gb3S9SC.dpuf

http://www.ancient-origins.net/news-evolution-human-origins/life-expectancy-myth-and-why-many-ancient-humans-lived-long-077889