by Haider Warraich
“Not long after our first child was born, my wife and I contacted my mother in Pakistan to see if she could come and stay with us for a while in Durham, N.C., where I was training to be a cardiologist. We were overjoyed when she agreed. But when she arrived at the airport counter to collect her boarding pass, she learned that her valid visa had been unceremoniously cancelled without any reason given.
“That she couldn’t come see her only granddaughter (and help out her parents) was devastating for all of us. But as two recent articles published in Current Biology show, the presence of grandmothers goes far beyond sentimental implications: They may be responsible for the success of the human species.
“First, some background:
“Evolutionary biologists have long been struck by two unique features of humans. The first is that we enjoy some of the longest life spans in the animal kingdom. In just the past 200 years, there has been an unprecedented increase in how long we live, not just in the richest countries but also in the poorest. We have moved so far away from our hunter-gatherer ancestors that their life spans are more similar to those of apes and chimpanzees than to modern human beings.
“This feature is coupled with another.”