article_snippet: Among natural fertility societies, the average duration of breast-feeding is 2 years and 4 months.
article_snippet: This is not much in relation to the maximum lifespan of our species, around 120 years.
article_snippet: It is even less if compared to our closest relatives: female chimpanzees suckle female chimpanzees young for 4 to 5 years, whereas the maximum lifespan for chimpanzees is only 60 years.