The fossils of humans offer much information about the time in which they lived, the age at which they died and what they fed, and that information is obtained, in large part, thanks to the tests carried out on human remains. In Atapuerca, here in Spain, we have one of the sites that gives us more information about the evolution of humans, whose remains date from the middle pleistocene, approximately 400,000 years ago.
Once the fossils have been found, science is advancing and improving analytical capacity with various tests, and now a new laser technique has revealed the moment when a human from that time left breastfeeding.
The owner of that tooth left breastfeeding between 2 and 4 years
This new laser-based technique has been used in the Complutense University of Madrid by an international group of scientists with samples of two hominids from the Atapuerca field, with the intention of specifying better the food they were carrying out.
To date, to know, it was studied the morphology of fossil teeth, and according to the form, they deduced what was the main type of food. Now, with this new technique called laser ablation They can take a step forward and receive information that until now was impossible to collect. In addition, they have analyzed samples of deer and bear teeth.
As he explains Nuria García García, author of the study, in Europa Press, one of the two human teeth was the one that offered more information:
We have detected a significant and abrupt change in the individual's diet. Although we must take the interpretation with caution, this alteration occurred in the section of the tooth that is formed when weaning occurs in children, something that seems very relevant to us.
And is that the tooth in question, a canine, reflects that between two and four years of that human there was an important change in the diet, which are associated with what is produced when a child stops receiving breast milk. Obviously, as has only happened in one tooth, scientists prefer not to secure it completely and leave open the possibility of confirming it with subsequent analyzes to other samples.
The other tooth, which is from another human, an incisor, does not show alterations throughout the formation of the tooth, although this does not rule out that in its case there were drastic changes in the diet, but that while the tooth was forming there was no such variation. As it is the central incisor, which is one of the first formed, they argue that the child probably stopped being breastfed after the tooth was ready.
Again, in García's words:
The molecules we eat when we eat are incorporated into all the tissues of our body, including hair, skin, teeth and bones. Since the teeth grow over time, we can analyze the molecules to find out if there have been changes in the diet.
And the teeth of the animals?
When analyzing the teeth of the animals, they also did not observe large variations in the analyzes. This means that there were no major changes in their diet over time, at least while the pieces analyzed were formed.
So when did natural weaning occur?
If we need to know this answer we will not have it thanks to this advance, or at least not for now. We talked about a single tooth, a single human, who could have left breast milk between 2 and 4 years old because it was the age when children stopped breastfeeding or it could be that, why not, his mother would die then and the baby would stop breastfeeding.
It will take many more teeth and many more analyzes to have more information about it and, obviously, it will be necessary for scientists to want to answer this question, because laser ablation has already been used before with Australopithecus three million years ago found in Africa in order to know what their habitat was like.
So for now there is no news about it and we continue to focus on what we know. As anthropologist Kathy Dettwyler told us in an interview we did on the blog the natural age of weaning goes from two and a half years to seven years.
