A fascinating report by an European group of archaeologists led by Julie Dunne of the University of Bristol, UK has appeared in the October 10, issue of Nature (574,246-249,2019), titled “Milk of ruminants in ceramic baby bottles from prehistoric child graves”. The group was able to isolate baby bottles, some with an oval shape and a handle and some others with a small spout through which liquid could be poured or suckled. The earliest one found was during the European Neolithic age (around 10,000 years ago) while some others were found in sites from the Bronze and Iron ages (4000-1200 BC).
What makes the Nature paper even more interesting is the finding that the ceramic baby bottles had some organic chemical residues stuck on in their walls and could be analysed. The group was able to extract those residues and analysed the molecules in them, using the latest chemical and spectroscopic methods. All the extracts contained fatty acids (such as palmitic and stearic acids) which are common in the milk of cattle, sheep and such domesticated animals and not in human milk! The authors conclude thus: ‘the finding of these three obviously specialized vessels in child graves, combined with our chemical evidence, strongly points to these vessels having been used to feed animal milk to babies (instead of human milk) and children during weaning, as supplementary foods”.
When did animal milk feeding start?
The above paper had referred to an earlier report by Rachel Howcroft and others, from the archaeological research labs of Stockholm University, Sweden, with the catchy title “The Milky Way: The implications of using animal milk products in infant feeding” in the journal called Anthropozoologica (47-31-43(2012; downloadable free on the net. I strongly recommend reading it by the interested. (Incidentally, the term Anthropozoologica refers to interactions between us humans and other animals). This practice of using animal milk to feed human babies would have started only after the domestication of animals, which would have occurred when humans started settling in communities, started farming and domesticating animals for various uses. This is believed to have happened in the Neolithic period around 12,000 years ago, first in the Middle East, later in parts of Western and Central Asia and in parts of Europe. Community living, agriculture and farming started, and animals such as dogs, cattle, goats, camels (and later horses) were domesticated and put to use for human needs. Until then we were hunter-gatherers, and the only milk that human babies had was their mother’s and weaning would have happened only after the infants grew to about two years of age.
The Neolithic Age changed the dynamics of human behaviour, fertility increased, the female work pattern had changed such that weaning of babies would also have started earlier. It also meant, as Howcroft and co-workers argue, that human babies were introduced to complementary food such as animal milk. This also appears to have enabled human mothers to vary their reproductive strategy (how many babies, how often and how early to wean).
We domesticated dogs anywhere between 10,000-4400 BC, cows and sheep around 11000-9000 BC, camels around 3000 BC and horses too around the same period. Yet we use only the milk of cows, goats and sheep not of the other animals mentioned above, although it appears that Africans did use camel milk, This choice of ruminants (that is, cattle, sheep, goat and camels, which have a compartmentalised stomach, where the food is quickly swallowed and chewed and sent off to the rumen, which is the main digestive system) seems to have came about through a trial and suitability experience by us. Note that we did/do not use milk from dogs or horses - wonder why?
How ruminant milk differs
Howcroft and co-workers, in their paper, have done a comparison of the contents of human and ruminant milks. Compared to ours, sheep milk has a higher solid component: less water, less carbohydrates, more protein and lipids and higher energy content. While the higher protein content might be related to the rapid growth of bottle-fed infants, it could also lead stomach acidosis and diarrhoea. Cow’s milk, with a slightly lower protein and fat content than sheep’s (though still three times higher than human milk), can also cause the same symptoms as sheep milk. Plus, ruminant milk lacks certain enzymes that human milk has, and thus is not as effective as human milk in fighting infection and in helping mineral adsorption. Given these differences, some protective and some deficient, it is best that ruminant milk is used as complementary to, rather than replacing human milk completely. This is what early humans did through observation and adoption. This also would have led them to invent and use “baby feeding bottles” and jugs made of ceramics.
The authors further argue that fermenting milk (which, upon storing, produces yoghurt) helps to preserve it, reduce the lactose level and help digestion, thanks to the level of the enzyme lactase. They conclude that “although the milky way may not have been the best for prehistoric infants, the yoghurt way could have been good both for them and for the spread of lactase persistence”.
Last, Vasant Shinde and associates from Pune had done extensive survey of sites from the Harappan Civilization in India, and have solid evidence of Ceramic Feeding bottle from the Harappan site of Kalibangan dated to 2500 BC. The Harappans too weaned their babies with animal milk. Which animal? If we can at all find any residues from these bottles, and have them analysed in our labs, a la Dunne, that would be exciting!
dbala@lvpei.org
