Since the name of the evolutionary game is survival and reproduction, the phenomenon begs explanation — why live longer than you can reproduce? In the 1960s, researchers came up with the “grandmother hypothesis” to explain the human side of things. The hypothesis is that the help of grandmothers enables mothers to have more children.
Two studies published Thursday [February 6] in Current Biology take another look at this hypothesis and add new insights into the role grandmothers play.
The first hard evidence for the grandmother hypothesis was gathered by Kristen Hawkes, an anthropologist at the University of Utah who was studying the Hadza people … in northern Tanzania. Hawkes was struck by “how productive these old ladies were” at foraging for food, and she later documented how their help allowed mothers to have more children.
The second study, conducted by Simon Chapman, a Ph.D. student at the University of Turku in Finland, looked at a database of preindustrial Finns to answer this question. From 1731 to 1895, all births, deaths and marriages were recorded by the state. … .
In Finland too, the presence of a grandmother boosted a daughter’s total number of offspring.
Read full, original post: Living Near Your Grandmother Has Evolutionary Benefits