Ancient bone could reveal how Neanderthals cared for a child with Down syndrome

Archaeologists found the fossilized ear bone at Cova Negra, a cave in the province of Valencia in Spain. (Valentín Villaverde / CNN Newsource)

A fossilized ear bone unearthed in a cave in Spain has revealed a Neanderthal child who lived with Down syndrome until the age of 6, according to a new study.

The find suggested that members of the community cared for and looked after the vulnerable child, who lived at least 146,000 years ago. The research is at odds with the image of Neanderthals, ancient human relatives who went extinct around 40,000 years ago, as brutish cavemen.

“The individual would have needed continuous and intensive care,” said paleoanthropologist Mercedes Conde-Valverde, the lead author of a study on the bone that appeared Wednesday in the journal Science Advances.

The child “suffered from severe loss (of) hearing and had serious balance issues and episodes of vertigo,” explained Conde-Valverde, who is an assistant professor of physical anthropology at the University of Alcalá in Spain.

Muscle weakness would have also made breastfeeding and movement difficult, she added.

The tiny fossil was excavated in 1989 from the Cova Negra archaeological site in Spain’s Valencia province. However, archaeologists only recently discovered the specimen when they combed through faunal fragments gathered at the site during a review of the material.

“We have been able to identify it as a Neanderthal due to the peculiar proportions of its semicircular canals, which are characteristic of Neanderthals,” Conde-Valverde said, referring to the inner tubes of the ear.

The study did not include precise dating of the bone, which would require extraction of ancient DNA, but Neanderthals occupied the site 146,000 to 273,000 years ago. The research team has not determined the sex of the young Neanderthal.

A surprising lifespan

People with Down syndrome can lead a long life today, but it was surprising the child lived beyond the age of 6, Conde-Valverde said.

Life in the Stone Age would have been demanding. The study noted that Neanderthals were highly mobile, regularly moving from place to place. The care required for the child to survive for an extended period of time likely involved the mother’s reliance on the cooperation and support of other members of the group.

Even in the recent the past, it was common for people with Down syndrome to die in childhood. According to the study, life expectancy in 1929 for children with Down syndrome, a condition caused by an extra partial or full chromosome, was 9 years. By the 1940s, the expected lifespan had increased to 12 years.

Today, about 1 in 772 babies in the United States are born with Down syndrome, and life expectancy now exceeds 60 years, according to the National Down Syndrome Society in the United States.

The oldest known case of Down syndrome in Homo sapiens, our own species, dates back at least 5,300 years. Using ancient DNA, the authors of a study published in February identified six cases in prehistoric populations. None of the children lived longer than 16 months.

Down syndrome has also been documented in chimpanzees. A January 2016 study highlighted the case of a chimp with Down syndrome that survived to 23 months thanks to the care received by the mother, with assistance from the eldest daughter.

However, when the daughter stopped helping to look after her own offspring, the mother was unable to provide the necessary care, and the offspring died, the study said.

Abnormalities in the inner ear

Conde-Valverde and her colleagues believe the bone belonged to a child with Down syndrome because of a series of abnormalities in the inner ear structure.

These include an abnormal shape of the lateral semicircular canal (the shortest ear canal); an enlarged vestibular aqueduct, a narrow, bony canal that goes from the inner ear to deep inside the skull, and a reduction of the overall size of the cochlea bone chamber.

“Some of these pathologies commonly appear in various syndromes, but the combination present in the Cova Negra fossil has only been described in contemporary people with Down syndrome,” she said.

Definitive proof that the child had Down syndrome would require the recovery of ancient DNA from the fossil, but that hadn’t yet been possible, she said.

Past studies of archaeological finds have suggested that Neanderthals cared for vulnerable members of their group.

One Neanderthal man buried in Shanidar Cave in what’s now Iraq was deaf and had a paralyzed arm and head trauma that probably rendered him partially blind, yet he lived a long time, according to October 2017 research.

A Neanderthal skeleton known as the “Old Man of La Chapelle” uncovered in current-day central France had degenerative arthritis and may have been fed by other members of his group, a February 2019 study found.

A child looked after ‘like any other’

Conde-Valverde said that the discovery of the Cova Negra fossil supported the existence of true altruism among Neanderthals.

“For decades, it has been known that Neanderthals cared for and looked after their vulnerable companions,” Conde-Valverde said.

“However, all known cases of care involved adult individuals, leading some scientists to believe that this behavior was not genuine altruism but merely an exchange of assistance between equals,” she said.

“What was not known until now was a case of an individual who had received extra-maternal care from birth, even though it could not reciprocate.”

Most parents today don’t view childcare as an “expectation of reciprocity,” and it was unlikely to be the case among Neanderthals, said Penny Spikins, a professor of archaeology at the University of York in the United Kingdom and author of “Hidden Depths: The Origins of Human Connection.”

Humans likely evolved an instinctive and emotional response to care for infants to ensure they survived, said Spikins, who wasn’t involved in the research.

“This find brings home how like us Neanderthals were in so many ways, particularly in our common human desire to care for the vulnerable,” she said.

“We can imagine that this child was loved and looked after like any other.”