Regarding the grandmother effect, I received this from Kathy Dettwyler,
Cathy Liles

Here's my comment, which you can forward to the list:  Many anthropologist
do not accept the whole notion of the "grandmother effect".  In fact, most
females of most mammalian species live to the age where their youngest is
weaned and capable of independent survival (which may be some years after
weaning).  There are other mammals, including other primates that go through
menopause and live beyond their reproductive years.  If you look world-wide
at how long women live in non-industrial countries (without access to
antibiotics, surgery, IVs, tube-feeding, chemotherapy, respirators, etc.),
the average life-span for women who survive to adulthood (i.e., they didn't
die as infants), the typical life span is about 60-65 years.  Not a lot of
women in traditional societies living beyond 60-65 years of age.  If you
also look at the average age of menopause (around 50) in these societies,
and the average age for independent survival, of around 10-15 years for
children, then there is nothing to explain.  Women live to the end of their
reproductive careers PLUS the time it takes them to successfully raise their
last child.  
 
Kathy Dettwyler

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