BOB HIRSHON (host):
Animal grandparents. I’m Bob Hirshon and this is Science Update.
We take the existence of grandparents for granted in human society, but grandparenting behavior hasn’t been documented in the animal world until now. Researchers studying Seychelles warblers on tiny Cousin Island in the Indian Ocean closely follow the lives of every bird from birth until death. According to evolutionary biologist David Richardson of the University of East Anglia, large numbers of older females that have been deposed from their territories by their own daughters stick around to help feed and raise their grandchildren.
DAVID RICHARDSON (University of East Anglia):
It’s a kind of surrogate way of increasing your reproductive success; increasing your genetic outputs, so to speak.
He says the grandparent birds aren’t too old to breed themselves. But overcrowding on the island limits the number of territories, making grandparenting a better option. I’m Bob Hirshon for AAAS, the science society.