We have this tremendous uncertainty now.

This would make sense when you look at humans and at killer whales.you might be using up food resources that could instead be used by your children.

by examining mortality and fertility rates along with urinary hormone levels in dozens of Ngogo chimpanzees.represents two decades of research into the Ngogo community of wild chimpanzees in Kibale National Park.the researchers were able to demonstrate that these females can live for many years after they begin to show the hormonal signs of menopause and cease to reproduce.

menopause is marked by the end of monthly menstruation.Previously this had only been documented.

by scientists from the University of California.

which both have tight-knit family groups with grandmothers often playing important roles as auxiliary carers for their grandchildren.The bag was flying just above Japan and out over the Pacific Ocean as of Wednesday morning.

a blog that tracks more than 28.Video taken by Moghbeli shows the bag floating away.

and the accidental destruction of two American and Russian spacecraft.NASA has been looking for ways to limit space debris since 1979.