Grans crucial for child survival

The mystery of the human menopause, which is almost unparalleled among mammals, has been explained by scientists: it apprently evolved to ensure grandmothers would survive to help with childcare.

Research has suggested that people whose mothers live for a long time after the menopause have more children than those whose mothers do not, showing that the female change of life seems to have an influence on a family’s reproductive success.

The results, from an analysis of 18th-century and 19th- century birth records, provide the strongest proof yet for the “grandmother hypothesis”, explaining why the menopause developed in apparent defiance of evolutionary theory, informs &to=http://www.timesonline.co.uk' target=_blank>Timesonline.co.uk

Most animals reproduce until they die but, in humans, women tend to live well after menopause, a reality that has long puzzled biologists.

Now, a new study by Finnish and Canadian researchers is suggesting why: It appears that older women are essential to the survival of the species. The grandmother hypothesis holds that a grandmother, even though she can no longer bear children herself, has a decidedly beneficial effect on the reproductive success of her children and the survival of her grandchildren.

Crudely put, granny's presence helps her children to breed earlier, more successfully and more frequently, and it helps to ensure that grandchildren grow up healthier, according to multigenerational research conducted in Canada and Finland, report &to=http://www.theglobeandmail.com' target=_blank>TheGlobeAndMail.com