Prehistoric baby bottles
Time to wind the clock back thousands of years, because scientists have found what they believe are the world’s oldest baby bottles. These tiny clay pots with spouts have been found all over Europe, and some date back over 7000 years ago. But no one was really sure what they were for. Now, archaeologists have managed to analyse the residues left by the material they once contained, helping to solve the puzzle. Phil Sansom heard from the study’s author Julie Dunne what their results say about ancient human societies...
Julie - So what we've discovered is essentially the first and the only evidence for the types of foods that prehistoric mothers were feeding their infants. And we discovered this in lovely little evocative baby bottles. Archaeologists have been coming across them firstly in the Neolithic in Europe, so that's about 7000 years ago, and then in the Bronze Age and Iron Age, and they’ve become a bit more common then.
Phil - And what do they look like? Are they like small teapots?
Julie - They're normally around about 10 centimetres wide and they have a spout, but they vary enormously. Quite a few of them are made in the shape of mythical animals.
Phil - Did you find a particular two or three that you wanted to look at?
Julie - Yes we did find three. So they actually were dug up some 20 or 30 years ago from a site in Germany and Austria.
Phil - What did you do to actually figure out what these are being used for?
Julie - Essentially how we find out whether they were to feed children was to go and look in children's graves, and they are very unusual to find. We had quite a search to find a few graves and find the vessels that had been contained within them. So just to explain, if you think of an unglazed ceramic pot, and if you were to put some water in it, and then some meat and boil that up, you would literally see fat floating on the top. It's these fats that absorb into the ceramic matrix of the pot. And very luckily for us, they sit in this pot for thousands of years, over archaeological timescales. So what we do is we use a technique called organic residue analysis. And normally we take broken pot shells from archaeological sites and grind them to a powder, but we couldn't do that in this case because they're so small and so precious so we couldn't half destroy them. So we make clean a little bit of the surface of them, just to remove any contamination from handling. And then I drill down enough powder to sample. I have to say it's quite nerve wracking when you're doing that to something you know is that old and that precious.
Phil - Then what do you do once you drill down a piece?
Julie - What we do is we use a methanolic acid extraction and this releases the molecules which are called lipids, and these are the fats and oils and waxes of the natural world. We then put them on what we call a gas chromatogram. And that tells us whether there's anything there. Once we've done that, they go on to a mass spectrometer and that tells us what the compounds we found are.
Phil - To clarify, you weigh it effectively in that mass spectrometer.
Helen - Essentially.
Phil - And what you get out matches what these animal fats should look like.
Helen - There's actually another step to that. What we need to do is look at the stable carbon isotope values of these particular fatty acids, and it's that that allows us to differentiate between types of fats. We can differentiate firstly between ruminants. So that would be cattle, sheep and goat. We can identify the difference between their meat and their milk. Other techniques enable us to find the processing of aquatic products, we can identify plants, and also the presence of beeswax which denotes honey processing. It's really based on the physiology of the animal.
Phil - And so when you looked at the fats that you found on these clay pots, what did you find?
Helen - Fascinatingly, all three pots contained ruminant milk.
Phil - That's cow or …
Helen - Cow, sheep or goat, yeah
Phil - You can't tell which one?
Helen - No, because their physiology is basically the same.
Phil - Okay, but it means that these kids from 7000 or so years ago were getting fed cow or sheep milk.
Helen - Yeah which is amazing.
Phil - What does that say about society back then?
Helen - So this all ties in to what begins to happen in the Neolithic at about 10000 years ago. People start to settle down, they domesticate animals and they also start to grow crops. This changes the way prehistoric mothers could feed their babies. Hunter-gatherer mothers tend to give birth every five years, but Neolithic mothers have much shorter inter-birth intervals, they tend to give birth every two years. And that's because of the availability of these foods. They're on these people's doorsteps, they’re on tap, and you're having more babies, the population increases dramatically. We call this the Neolithic Demographic Transition. People start moving out across Europe. This leads to larger settlements and eventually to the growth of cities.
Phil - So it's like, if you've got milk from other animals you can have more babies. This is like the missing link to humans growing.
Helen - Essentially, yeah. In a way, that's why we're here today.
Phil - What about the fact that they've spent so much time making these pots, what does that say?
Helen - When a prehistoric mother or father perhaps is giving their infant this little pot, they're not just giving the child a pot to drink from, they're giving them some little object that's probably going to make the baby smile or laugh, they're incredibly cute. And I think it tells us an enormous amount about the love and the care and the attention that these prehistoric parents would have had for their babies.