Living in society and caring for others is probably what has allowed our species not only to survive but also to evolve over billions of years.
At least that is the theory of many scientists, which has recently been reinforced by the results of A study in Spain focused on a small bone of unusual characteristics.
At the Cova Negra rock art site, located near the Spanish city of Valencia, a team of paleontologists discovered in 1989 a 5-centimeter bone fragment that came from the inner ear of a 6-year-old Neanderthal.
Although the bone has not allowed to determine if it belonged to a boy or a girl, the team that analyzed it christened the individual Tina.
The discovery of a part of a Neanderthal’s ear canal is unusual. Normally, the remains are body parts such as the skull, teeth or limb bones. And although at that time, other remains from the excavation were of more archaeological interest, Researchers determined that it was actually a very valuable piece.
Neanderthals populated Europe for hundreds of thousands of years until they became extinct 40,000 years ago. They are one of our closest known relatives. A wise man (modern humans) and Neanderthals (Homo neanderthalensis) are classified as different species of hominids, which coexisted over time and come from a common ancestor.
The fossil is estimated to date back to the Upper Pleistocene and was therefore between 120,000 and regarding 40,000 years old.
“The real surprise came with the CT scan because revealed that this Neanderthal had birth injuries that correspond to Down syndrome and which would have also caused significant health problems throughout his life,” Professor Emeritus Valentín Villaverde Bonilla, from the Department of Prehistory, Archaeology and Ancient History at the University of Valencia, who led the Cova Negra excavation team, told BBC Mundo.
Threats to their survival
Villaverde explains that the damage detected in the fossil indicated that Tina had suffered from repeated ear infections, deafness, balance problems and probably mobility difficulties..
“She faced significant difficulties that threatened her survival. Obstacles that would have been impossible to overcome on her own,” she added.
Down syndrome is a genetic disorder in which a person has an extra chromosome that can cause varying degrees of intellectual disability, as well as heart, digestive and other organ problems.
And yet, Tina reached the age of 6, which far exceeds the usual life expectancy. of children with Down syndrome in the prehistoric population.
For comparison, at the beginning of the 20th century, between the 1920s and 1940s, the survival rate for a child with Down syndrome was between 9 and 12 years.
The explanation found by the team from the University of Alcalá that received Tina’s small bone to analyze is that the care necessary for her survival over a period of several years probably exceeded the mother’s capabilities and would have required the help of other members of the social group.
Their findings were published in July by the prestigious journal Science Advances. The key question that science is asking is whether such care They were altruistic – a behavior of great adaptive value – or self-interested.
After all, the Neanderthals were groups of hunter-gatherers with high mobility across very large territories. “If you don’t pay special attention to this child, would not have survived to the age of six”Villaverde says.
Behavioral implications
Neanderthal caring for disabled people has long been known, but there is debate regarding the implications of this behavior.
While “some authors believe that care It took place between individuals capable of reciprocating the favor, others maintain that the care was produced by a feeling of compassion related to other highly adaptive prosocial behaviors,” the study authors say.
Mercedes Conde Valverde, a researcher at the Chair of Evolutionary Otoacoustics at HM Hospitales and the University of Alcalá, spoke to BBC Mundo from Atapuerca. This academic led the team of Spanish researchers in charge of analysing Tina’s small bone.
“There are remains of other Neanderthal individuals with pathologies that probably required the help of the group. But all of them were adults and they were diagnosed with pathologies that they were not born with, but rather acquired throughout their lives: wounds, illnesses, broken bones and other traumas,” he specifies.
“The debate regarding this behavior is whether, when you are an adult, being helped by the group is really a good behavior. altruistic – I help you because I feel like it – or it is a behavior of reciprocal help -I help you because you helped me in the past or because you will help me in the future-“, he clarifies.
As altruistic as we are
Tina’s case is exceptional because she is a girl, she was born with these problems and yet she survived at least six years. “This means that they had to help her a lot and take care of her, but since she is a girl, it is most likely that They wouldn’t expect me to return the favor”says the researcher.
The study of children with serious pathologies is particularly interesting, since children have a very limited possibility of reciprocating care. What it says regarding the evolution of our species is that Neanderthals had altruistic behavior or as altruistic as we have.
There is a known case of A chimpanzee with Down syndrome who survived to 23 months age thanks to the care received from her mother, who was assisted by her eldest daughter.
When the daughter stopped helping the mother to care for her own offspring, the mother was unable to provide the necessary care and the offspring died.
If Neanderthals were compassionate and so are we, but we are two different evolutionary lines, “this means that At least the common ancestor probably already had it and that’s why both lines inherited it.”, explains Conde Valverde.
That human species that gave rise to the Neanderthals and Homo Sapiens lived a million years ago.
“What we propose is that other members of the social group “They might help the child directly or they might help the mother, relieving her of tasks that she had to do so that she might take care of Tina. Neanderthals were a species very similar to us,” he adds.
That is, care among Neanderthals would be related to a broader and more complex social context, of great adaptive value, and the study of children offers the possibility of testing whether care is directly related to a social strategy as complex as collaborative parenting.
“On the one hand, The most critical ones maintain that it is not possible to rigorously infer the existence of care from mere paleopathological evidence and that the inferences made are based on unjustified assumptions. However, in recent years the idea that paleopathological evidence is an objective source of information on the existence of care in prehistory has been gaining ground,” the study reads.
Another particularly interesting aspect in the field of bioarchaeology of care applied to fossil hominids is to determine why people dedicated part of their time and effort to caring for a member of their group with a temporary or permanent disability.
This discovery “seems nice to me because makes the group of people with Down syndrome visible. We are all already in the evolution human, we all have a reference and we can all represent ourselves, we have always been there, we have always traveled together,” says Ignacio Martínez Mendizabal, co-director of the Chair of Evolutionary Otoacoustics and Paleontoanthropology Research at the University of Alcalá.
“And then there is a more technical, deeper, scientifically speaking, issue of evolutionary biology, which is the question of When and how does this very human behavior arise?because it is uniquely human to care for vulnerable people within communities.”
“I truly believe that there is no other team in the world right now that would have been able to, with this fossil, realize what it had and, above all, carry out all the research and manage to publish it in a journal like Science Advances,” concludes the professor.
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