This is CBS, I on the world. I'm John Bachelor and I step into a time machine thanks to Nature magazine and go 50,000 years ago.

I welcome Jennifer Miller and Yimming Wang of the

Department of Archaeology Max Planck Institute for the Science of Human

History in Vienna, Germany, publishing in the peer-reviewed top-of-the-pile magazine, Nature,

Ostrage Eggshell Bees reveal 50,000-year-old social network in Africa.

Jennifer and Yiming, congratulations in a very good evening to you.

First, I want to speak of the circumstance of finding ostrich eggs in southern Africa and in eastern Africa.

Let's go to southern first.

These are rock shelters.

Jennifer, what is a rock shelter and how are these eggs how are these beads found what how do they

dig them out are they all together or are they distributed around a large area good

evening to you good evening thank you so much for having us.

Rock shelters are sort of just a rocky overhang, so not necessarily surrounded on three sides the way that we might think of a cave,

but a lot of these sites tend to be rock shelters or caves because they were places that

people would have wanted to live in the past and they're also

places that would accumulate material and leave it well preserved for archaeologists

to find. So on excavations today, archaeologists will go and sift through the sediments and often recover these

beads usually in isolation in the screen often as we sieve the

sediments and we we sort of come across all of these beads in the screen and so

it's the same in eastern and in southern Africa that we find typically in

rock shelters or caves and that we recover these beads sorting through the sediments.

There are surprising revelations here but first we have to

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