Not Exactly Rocket Science

i-8417f01aae6773d1e716802b50ac5e49-Cranium14.jpg

Blogging on Peer-Reviewed ResearchFor all appearances, this looks like the skull of any human child. But there are two very special things about it. The first is that its owner was clearly deformed; its asymmetrical skull is a sign of a medical condition called craniosynostosis that’s associated with mental retardation. The second is that the skull is about half a million years old. It belonged to a child who lived in the Middle Pleistocene period.

The skull was uncovered in Atapuerca, Spain by Ana Gracia, who has named it Cranium 14. It’s a small specimen but it contains enough evidence to suggest that the deformity was present from birth and that the child was about 5-8 years old. The remains of 28 other humans have been recovered from the same site and none of them had any signs of deformity.

These facts strongly suggest that prehistoric humans cared for children with physical and mental deformities that would almost have certainly prevented them from caring for themselves. Without such assistance, it’s unlikely that the child would have survived that long.

Before moving on, a point of clarification: when I say “human” in this piece, I mean the genus Homo, which the child certainly belonged to, rather than the species Homo sapiens, which it certainly did not (its skull is too old).

i-a8cae38df37167130cb55f739d646542-Skull-endocasts.jpgGarcia found Cranium 14 in many different pieces over two years, but the fragments were preserved so well that she could reconstruct the skull very accurately. On doing so, she found it clearly belonged to an immature child. Its brain volume was within the adult range, but certain connections between the different bones of its skulls hadn’t fully matured. Based on that, Garcia guesses that the child was about 5-8 years old when he or she died.

Garcia also found that two of the bones in the child’s skull – the left parietal and occipital – had fused far too prematurely. When humans are born, our skulls consist of 45 different bony elements. These plates are separated by connective tissue and they can move and flex against each other. That’s necessary to allow for the growing brain room to expand. As a child matures, the bones of its skull start to fuse together and lose mobility. Eventually, many become joined by rigid sutures.

In Cranium 14, one of these sutures – the lambdoid suture – had closed too soon on the left side but not on the right. This premature fusion restricted the growth of its skull and as a result, it had become twisted and asymmetrical – a condition known as craniosynostosis. It’s a rare disorder, with cases involved the lamdoid suture affecting just 1 in 40,000 babies.

It’s not clear why the child’s skull developed abnormally. Even for modern humans, the causes of craniosynostosis are difficult to work out, but Gracia has some ideas. The dimensions of the other bones and sutures suggest the lamdoid suture fused while the child was still in the womb, during the third trimester. The timing suggests a couple of possible causes – some sort of physical trauma experienced in the womb, or a metabolic disease like rickets or anaemia. Of these options, Gracia thinks that trauma is the more likely, for rickets and anaemia tend to develop after birth.

Whatever the cause, the early closure of the lamdoid would have put a lot of pressure on the growing brain. This condition has been linked to mental retardation and motor problems in modern-day children. With such disabilities, the Cranium 14 child would have been unable to reach the age of 5-8 without the care of its peers.

Gracia says, “It is obvious that [this] hominin species did not act against abnormal/ill individuals during infancy.” There are a couple of other specimens that support this idea. One skull recovered from Georgia was 1.77 million years old and the owner had clearly lost all but one of its teeth several years before it died. According to the authors, the individual may have depended on others to make up for their inability to chew. Another skull unearthed in China showed signs of a substantial head wound that had subsequently healed.

That may not be surprising news for some of us, but remember that humans have not always behaved in such an altruistic way throughout our history. As just one example, the bones of several children with craniosynostosis were uncovered in the cemetery of the Medieval Hospital of St James and St Mary Magdalene in Chichester, England, a 15th century almshouse where deformed children were clearly abandoned.

Reference: Gracia, A., Arsuaga, J., Martinez, I., Lorenzo, C., Carretero, J., Bermudez de Castro, J., & Carbonell, E. (2009). Craniosynostosis in the Middle Pleistocene human Cranium 14 from the Sima de los Huesos, Atapuerca, Spain Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.0900965106

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Comments

  1. #1 Zach Miller
    March 30, 2009

    Okay, here’s a potentially horrible question: Why would it be advantageous to “sink” your group’s resources and energy into a “dead-end” kid? If this was half a million years ago, and humans were still hunter/gatherers, that’s some serious sacrifice! What are the evolutionary advatages to keeping “flawed” (genetically) individuals alive? Do other animals try to keep unfit babies alive in the same way?

    Or is this the result of our overriding desire to care for our young? That is, have we sacrificed triage because we’re so dedicated to raising very few young?

  2. #2 Moth Eyes
    March 30, 2009

    Zach – this doesn’t have to be adaptive, but can be a by-product. So you can have a behaviour like “care for the kid” – a pretty good behaviour generally, but might not have a specific adaption turning it off for “dead-end” kids.

  3. #3 Romeo Vitelli
    March 30, 2009

    How severe would the child’s impairments have been? Occurrence of craniosynostosis can vary widely in children depending on severity and whether there are other abnormalities as well. It may not be possible to make a clear determination on how much a burden the child was on others based on the skull alone.

  4. #4 Brian Schmidt
    March 30, 2009

    So the harder question would be whether deformed individuals are under-represented in fossil finds, and if so whether the underrepresentation resulted from neglect/abandonment. A few examples doesn’t rule out this possibility.

    Years ago I worked with a hill tribe group in eastern Burma. I was struck by the fact that I only saw two children my entire time there with birth defects, one of whom lived with a preacher. I had some suspicions.

  5. #5 Rob Jase
    March 30, 2009

    Can we be sure this wasn’t the alien Starchild’s cousin or something?

    I have a headache.

  6. #6 HP
    March 30, 2009

    As a child (late ’60s – early ’70s), I remember reading about a Neandertal skeleton that showed advanced age (well past reproductive peak — maybe 35 or 40), multiple healed skull fractures, and advanced arthritis. It must’ve been a fairly well-known case for me to have heard of it as a kid. Anyway, it was held up as evidence that Neandertals cared for the sick, injured, and elderly.

    For years afterward, in popular depictions of Neandertals, they’d often include a depiction of that guy. Blind on one eye, staggering along on a badly-set broken leg and arthritic joints. And I’d see it and say, “Hey, it’s that guy.”

    I haven’t heard much about that guy in the last 20 years or so. I know they’ve since discovered that, a) arthritis and bone fractures are fairly common in elderly chimps in the wild, yet chimp troupes don’t just abandon them to their fate, and b) Neandertals were apparently tough as nails, and massive healed injuries that would’ve felled a gracile sapiens were apparently quite common.

    So, to tie this back to your post, I find myself completely unsurprised that a 500Ky-old human with multiple birth defects would survive as long as feasible.

    Anyway, I still wonder about that one guy from time to time. He was the first extinct hominin I ever got to know as an individual.

    Does anyone know the individual Neandertal to whom I refer? And what’s the current thinking?

  7. #7 boo
    March 30, 2009

    HP, sounds like the “Old Man of La Chapelle-aux-Saints”:
    “Many of the teeth were missing, and the bone that had surrounded these teeth showed evidence of healing after tooth loss. This means that the individual lived for a considerable time after losing many of his teeth.”
    http://anthropology.si.edu/humanorigins/ha/lachap.htm

  8. #8 Lilian Nattel
    March 31, 2009

    It’s amazing how much can be learned from a skull and bones. Altruism is part of the spectrum of human behaviour as is cruelty. It’s not surprising to see that behaviour go far back.

  9. #9 Marcin Ryszkiewicz
    March 31, 2009

    Hi HP, your Neanderthal guy was from Shanidar in Iraq (about 60 000 years ago), unearthed in 1960 by Ralph Solecki. He was also known as Old Man (or Nandy), not to confound with that from La Chapelle-aux-Saints. I reconstructed the scene of his burial on the exhibition here in Warsaw :)

  10. #10 Damien R. S.
    April 3, 2009

    “It is obvious that [this] hominin species did not act against abnormal/ill individuals during infancy.”

    That seems like a rather amazing generalization to leap to. The only thing that’s obvious is that this individual wasn’t acted against. It tells us nothing about what was normal, if that even makes sense across different environments. Chimps and humans vary in their parenting based on personality and circumstances, why wouldn’t these hominins?

  11. #11 Pen
    July 11, 2009

    Most modern day children are pretty much of a burden till they reach 5-8 years aren’t they? I wonder what the child died of and until when it would have been cared for?

  12. #12 Phimon
    July 18, 2009

    Is this the most ancient skull with craniosynostosis in the world? Any others?

  13. #13 van veelen
    August 7, 2009

    Isolated lambdoid synostosis is only in a minority of cases associated with mild cognitive or motor delay, this in contrast to multiple suture synostosis. The kid was probably just looking a little bit funny.

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