The chalk mound

There's something about the mysterious that invites attention.  Curiosity is built into the human mind; it's just not in us to say "we don't know what this is, and probably never will," and forthwith let the matter go. 

Our deep and abiding fascination with the unexplained has its positive aspects, of course.  It's largely what drives science.  On the other hand, it can sometimes impel wild speculation -- and the less hard evidence there is, the broader the field is for fancy to take hold.

Take, for example, Silbury Hill, near Avebury, Wiltshire, England.  The area has been occupied for a very long time.  If you're an archaeology buff, you undoubtedly know about the Avebury Ring, a stone circle a little like Stonehenge that appears to have been built for some unknown purpose on the order of five thousand years ago.  Like the other stone circles in England, Scotland, Ireland, and northern France, the Avebury Ring is surmised to have had some sort of ceremonial purpose, but what exactly that might have been is a matter of conjecture.

Silbury Hill, though, is even more puzzling.  It's a forty-meter-tall conical chalk mound, a little less than one hundred and seventy meters in diameter at the base, making it similar in volume to the Egyptian pyramids (which were built around the same time).  It has been the subject of repeated archaeological investigations since the seventeenth century, with shafts drilled down into it vertically from the top and horizontally into the side, and what's been brought up is nothing more than the chalky local soil and fragments of branches from native plants like oak, hazel, and mistletoe.  The few bones found there were from oxen and deer, and date from about 4,500 years ago, so about the same general era as the Avebury Ring was built.

Other than that, and a handful of tiny artifacts of uncertain provenance... nothing.

It does really appear to be just a gigantic mound of clay and chalk.

[Image licensed under the Creative Commons Photograph by Greg O'Beirne, SilburyHill gobeirne, CC BY-SA 3.0]

Why would people build something like this?  Whatever the reason, it must have been important to them; a 1974 study estimated that constructing it -- moving and shaping the 250,000 cubic meters of heavy soil that composes it -- would have taken eighteen million person-hours.  Put another way, it would take five hundred strong individuals, working eight hours a day, fifteen years to create something like Silbury.

Naturally enough, the oddity of the structure, and its lack of any obvious purpose, has led to some bizarre speculation.  In the sixteenth century, the locals believed it had been created when the Devil brought a gigantic bag of dirt with which he intended to smother the town of Avebury, but the priest of Avebury prayed to God to intercede.  God forced Satan to drop his burden prematurely, creating Silbury.  Another legend is that a monarch named King Sil is buried inside the mound, his skeleton riding a gigantic statue of a horse made of solid gold -- but needless to say, no evidence of that has been forthcoming.  (As far as King Sil, he probably didn't exist in any case; the name Silbury seems to come from the Old English selebeorg, meaning "barrow hall.")

Even later investigators weren't immune to attributing Silbury to wild legends; eighteenth-century amateur archaeologists William Stukeley and Edward Drax thought the mound was connected to the Greek myth of the god Apollo killing the monster Python and burying him under a mountain.

Needless to say, no evil dragons were found by the excavations, either.

In the end, we're left with a mystery.  Silbury Hill was built by some extremely dedicated Neolithic Britons, but toward what end, we have no idea.  It's certainly curious, rising above the flat Wiltshire plains like the cone of a small volcano, and to this day it attracts tourists.

We are drawn to puzzles -- even if in this case, it's very likely one we'll never be able to solve.

****************************************

All in the family

Archaeologists and paleontologists are up against the same problem; bones and other fossils only get you so far.

There are cases where fossil evidence can give you some hints about behavior -- patterns of tracks, for example, or the rare case where the positions of the fossils themselves give you a picture of what was going on, like the recent discovery of an opossum-sized mammal, Repenomamus, attacking a much larger dinosaur, Psittacosaurus.  The pair of fossil skeletons were preserved, locked in a battle to the death -- the death of both, as it turned out, because they were both engulfed mid-fight in a mudslide.

But such lucky finds are rare, and inferences of behavior from fossils are usually sketchy at best.  This is why the study of a group of Neolithic human skeletons found near Gurgy-les-Noisats, France, 150 kilometers southeast of Paris, was so extraordinary.

The level of DNA analysis now possible allowed the analysis of the genomes of 94 of the 128 individuals buried at the site, to the level that the researchers not only were able to construct a seven-generation family tree for them, but make a guess as to what each individual looked like.

The analysis found that the bodies were buried in family groups -- the more closely two people were related, the closer together they were buried -- and that women who were not descendants of the original couple were mostly completely unrelated, suggesting they'd come into the family from another community.  Just about all the males at the burial site, on the other hand, were related, leading the researchers to conclude that men in this community tended to stay put, and at least some women did not.

Another curious thing was that the study detected no half-sibling relationships.  All of the sibling groups were from the same mother and father.  In this family group, at least, monogamous relationships were the norm.

Of course, there's a lot we still don't know; while this is a stunning accomplishment, it still leaves a great many questions unanswered.  For example, were the "outsider" women brought in because of a custom of outbreeding, or by conquest/capture?  What were the religious practices and beliefs that led these people to bury family members near each other?  Was the monogamy shown in this family universal in this culture, or was this grouping an exception for some reason?

It's an intriguing piece of research.  "This type of work really breathes new life into our understanding of ancient peoples," said Kendra Sirak, an ancient-DNA specialist at Harvard Medical School in Boston, Massachusetts, who was not involved in the study.  "I'm especially curious about the man at the root of the family tree.  I would love to know what made this person so important."

And given that a significant percentage of my ancestry comes from central and western France, I have to wonder if anyone in this family tree is a direct ancestor of mine.  There's no way to find out, of course, but the thought did cross my mind.  It's kind of eerie to think when I look at those facial reconstructions, one of those faces looking back at me might be my great-great (etc.) grandparent.

****************************************

Whoozagooboy?

It will come as no surprise to long-time readers of Skeptophilia that I am a dog person, given how often they come up in my posts.

Dogs, in general, like me way better than people do.  Years ago I went over to a friend's house for the first time, and she warned me about her neurotic, high-strung dog who -- direct quote -- "you should just ignore because otherwise she freaks out."  Within fifteen minutes, said high-strung dog was lying next to me on the couch, head in my lap, snoring.

My own dogs, Guinness and Lena, are a bit of an odd pair themselves.  Guinness is a pit bull/husky mix who is sweet and cuddly sometimes, and at other times seventy pounds of spring-loaded bounce. 

"I'm ready for my close-up, Mr. DeMille."

Lena, on the other hand, is a redbone/bluetick coonhound cross who is beautiful, laid-back, and has the IQ of a PopTart.  We had a good laugh at her yesterday because we called to the dogs out of our second-floor window, Guinness immediately looked up, saw us, and started wagging, whereas Lena spent the next fifteen minutes looking behind trees and bushes, wondering where Mommy and Daddy were hiding.

She never did find us.  Mommy and Daddy are pretty damn intrepid.

"Hi!  I love you!  You look familiar!  Who are you, again?"

So it's no wonder that I'm fascinated with dog behavior, and also the history of the human/dog association.  Which is why I was really excited to read about some research done jointly by Historic Environment Scotland and the National Museum of Scotland to reconstruct an ancestral dog from a 4.500 year old skull found in the Orkney Islands.

This Neolithic pooch was one of 24 dog skulls found at Cuween Hill, a burial site dating from about 2,500 B.C.E.  Archaeologists have surmised that this sort of thing generally means that the animal in question was some sort of totem; other tombs in the Orkneys have had similar deposits, one of the bones of sea eagles, the other of red deer.

"Perhaps the people who lived in the [Cuween Hill] area at the time saw themselves as 'the dog people'," said Alison Sheridan, principal archaeological research curator in the department of Scottish history and archaeology at the National Museum.  Whether or not that's true, these people, she said, clearly had a "special association" with their dogs.

"When you look at a Neolithic dog, it somehow communicates human relationships, and I can relate to that," said Steve Farrar, interpretation manager at Historic Environment Scotland.  "I can empathize with the people whose ingenuity made Orkney such an enormously important place.  When this dog was around, northwest Europe looked to Orkney."

So without further ado, here's a photograph of the reconstruction:

I think we can all agree that this is definitely the face of a Good Boy.  [Image courtesy of Santiago Arribas/Historic Environment Scotland]

So the dog/human relationship has been around for a long, long time.  Doesn't surprise me, really, given how easily they find their way into our hearts.  But I'm going to have to wind this up, because Guinness wants to play ball, and y'know, priorities.

**********************************

Monday's post, about the institutionalized sexism in scientific research, prompted me to decide that this week's Skeptophilia book recommendation is Evelyn Fox Keller's brilliant biography of Nobel Prize-winning geneticist Barbara McClintock, A Feeling for the Organism.

McClintock worked for years to prove her claim that bits of genetic material that she called transposons or transposable elements could move around in the genome, with the result of switching on or switching off genes.  Her research was largely ignored, mostly because of the attitudes toward female scientists back in the 1940s and 1950s, the decades during which she discovered transposition.  Her male colleagues laughingly labeled her claim "jumping genes" and forthwith forgot all about it.

Undeterred, McClintock kept at it, finally amassing such a mountain of evidence that she couldn't be ignored.  Other scientists, some willingly and some begrudgingly, replicated her experiments, and support finally fell in line behind her.  She was awarded the 1983 Nobel Prize in Physiology and Medicine -- and remains to this day the only woman who has received an unshared Nobel in that category.

Her biography is simultaneously infuriating and uplifting, but in the end, the uplift wins -- her work demonstrates the power of perseverance and the delightful outcome of the protagonist winning in the end.  Keller's look at McClintock's life and personal struggles, and ultimate triumph, is a must-read for anyone interested in science -- or the role that sexism has played in scientific research.

[Note: If you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]