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What We Know and Don’t Know So Far

By John Hawks

Monday, Nov. 18 — It’s a rare quiet morning here at Rising Star as we give the underground team the morning to tour Sterkfontein Caves, just a kilometer away (read about their day off). You might think that going into another cave wouldn’t be a break, but you get into Sterkfontein by walking, not creeping down a 12-meter squeeze.

Meanwhile, the science team is thinking hard about how to proceed, including deciding what information we can share immediately.

Skull man Darryl de Ruiter's face illustrates the degree to which anyone is sure of the species of what has been found here. (Photo by Andrew Howley)
Skull man Darryl de Ruiter’s face illustrates the degree to which anyone is sure of the species of what has been found here. (Photo by Andrew Howley)

In my last post (“In the hot seat”), I explained how we are making this the most open paleoanthropological excavation ever. In this one, I’ll explain why we aren’t answering many of the questions people have been asking on Twitter, by Facebook, and email. “What species is it?” “How old are the fossils?” “How many individuals are there?”

It’s simple: We don’t know. Believe me, we wish we did!

The usual approach to paleoanthropology — what I’ll call “legacy paleoanthropology” — is to keep all details quiet until a first publication appears. For a major discovery, that first publication is usually in a high-profile journal like Science or Nature. That publication may be years after the fossils are found.

The first publication answers those basic questions, “What species is it?” “How old are the fossils?” “How many individuals are there?” The millions of people who follow paleoanthropology usually find out about the research second- or third-hand, by press release.

That highly controlled approach creates the misconception that fossils come out of the ground with labels attached. Or worse, that discovery comes from cloaked geniuses instead of open discussion.

We’re hoping to combat these misconceptions by pursuing an open approach. This is today’s evolutionary science, not the science of fifty years ago.

It will take many months, even years, to make the careful comparisons needed to answer these elementary questions. This isn’t the kind of science that can be crowdsourced. Just as it takes training to go into that cave, it takes training to be able to carry out the kind of analyses we’ll be doing on these fossil remains. Our approach will bring in young scientists to work with the collection, building a collaborative team and documenting our work as we go.

That’s another way that our approach differs from legacy paleoanthropology. After the initial publication appears, the legacy model continues to keep many details quiet, as a small group of scientists assemble a fuller description of the fossils. During this twilight period, some teams allow outside scientists to examine their collections. Other teams bar outside scientists altogether, sometimes for many years.

That hasn’t happened with the Malapa Project, and it will not happen with Rising Star.

Here’s a quick FAQ of what we know now:

How many fossils are there? There are today more than 400 individual fossil specimens out of the cave. Much more bone remains in the soft sediments. Many of the pieces we have topside are small fragments. Many others are complete bones or easily identifiable large pieces. The advance team has been incredibly meticulous removing every fragment of bone, and many of these fragments we will be able to fit back together.

How many skeletons are in the deposit? We have only been able to work in part of the advance chamber, and we are excavating in only one very small area. We don’t know how many hominin individuals will be uncovered. We do know that the bones today represent multiple individuals, as single parts are represented multiple times.

What species do the fossils represent? We don’t know. We really don’t. They are not modern humans, but beyond that we are not speculating. I expect we will not have an answer to this question for many months.

What is the date of the fossil deposit? We don’t know. We are still recovering fossils from the surface, where they have been disturbed by people or natural processes in the past. The advance team has excavated a small area and has found abundant bone within the sediment in that area. We will work to find any areas of the cave where speleothems (calcite formations formed by cave processes) will connect to these sediments.

Can you tell me the context of the fossil remains? The floor of the advance chamber is a soft sediment with substantial moisture. Fossils are on the surface and within the sediment. We do not yet know how much material lies beneath the surface, or whether the fossils may have been redeposited from another location in the cave.

Will there be DNA in the fossils? We don’t know. Our excavation priorities right now are safety for the advance team and survey of the fossil-bearing deposits. We will be evaluating the fossils over several months to assess their state of preservation. What we do know is this site lacks the factors that are known to aid long-term preservation of DNA, such as low year-round temperature.

So if you don’t know any of these answers, what use is it to release anything? We’re here sharing science. Science isn’t the answers, science is the process. As we move through the analysis of these remains, we are going to continue to share what we’re doing. We are confident that will improve the science.

Aren’t you afraid that other scientists will scoop your results? The most important implication of open access is the change in the scientific culture. When you have a culture of secrecy, you breed people who trade in secrets. When you have a culture of openness, you must train people in responsible sharing. Our team and the curatorial practices at the University of the Witwatersrand will facilitate collaboration and sharing of datasets, and we expect the field will embrace these open standards.

I’m now watching the computer render the last 3-d scan of the chamber surface. We’re pushing the technology in every way we can, from our remote comms and cameras into the cave to the 3-d registration of pieces taken out of the site.

But our most important innovations have been down in the cave, finding ways for our team to work together.

After a week of running the operation, the advance scientists have fallen into a rhythm of approximately half-day shifts, staged into and out of the cave on a rotation. The first cavers go in around 7:15am, the last come out after 4:00pm. Getting into this cave requires several experienced cavers in place to assist the advance scientists entering and leaving the advance chamber. Some serve shifts inside the cave at key locations where they can support the scientists. Others are on hand at the cave entrance to run supplies in and fossils out. And the science team and command team are aboveground coordinating action and cataloguing and conserving the fossils.

We saw the incredible teamwork in action on Friday evening, as more than a dozen of the cavers and advance team carefully brought out a large skull fragment. Two scientists and two cavers staged it carefully up the Chute, seven handed it down Dragon’s Back, three more brought it through the Post Box — at the end with one scientist pulling our expert caver Rick Hunter through by the legs. All of this without so much as tipping the box containing the fossil.

As we move forward, we are building an even larger team, and our challenge will be to maintain that collaboration and collegiality. It’s a real challenge, because our field is so accustomed to a different style of interactions. But we owe it to this team of excavators working down in that advance chamber.

 

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Comments

  1. Maria S
    USA
    March 6, 11:05 pm

    Good question Michael. Remember, you need to realize that over time the Earth shifts. At the time these people died and were left behind, the caves may have had an opening directly accessible to the people of the time….perhaps a hole in the ground that lead directly to the cave that bodies were dropped down for “burial” or perhaps a wider opening that didn’t need “crawling” to access. You are right. Depositing the bodies here might have been part of the burial ritual, even if there are no direct signs of a ritual. How we see the cave today is probably no way how they saw the cave then. It would be interesting to see if a geologist can look at the layers and tell how the Earth looked then. It is pretty amazing! I would love to hear more about this, too!

  2. Michael B
    Australia
    January 21, 10:08 pm

    Like Steve M I am interested in how the bones got there and how they came to be lying as they are in the sediment. If it is difficult for the cavers to get to the site, how would the ancient individuals have got there, and why would they have taken the trouble to go to such a spot. The thoughts of squeezing my way down into the darkness (no head lights then) gives me the shivers to think about it. Are there signs of any ritualistic reasons for the bones to be there?

  3. P Boshoff
    South Africa, Pretoria
    January 10, 4:15 pm

    As team leader under whose guidance this find was made I can with a great sense of surety declare that we will find more hominin containing sites. Rising star is but one of well over 400 caves in the area and we have been finding Pliocene-Pleistocene aged fossils going down almost every cave we re-reconnoitered so far. Working with a wonderful person like Prof L.R. Berger and all my other beloved colleagues whose help, advice, and expertise (and sometimes reprimand) I thoroughly appreciate as well as the help advice and expertise of numerous other scientist this wondrous adventure – looking for more hominin sites and introducing them to the world for scrutiny can only be successful. We as an exploration team vow to do our outmost best in locating each and every sites possible still to be found in the Cradle and adjacent regions and will keep all with an interest posted as we intend to remain true to the pursuit of true science and the love of sharing it with all
    Thanking you all for your support and interest
    Pedro

  4. Alice C. Linsley
    USA
    November 27, 2013, 5:09 pm

    Keep up the great work. This is so exciting!

  5. Eric
    USA
    November 24, 2013, 7:23 am

    Are these bones, or fossils? Bones wouldn’t have lasted, but did they fossilize there in that sediment?

  6. LeonardoV59
    Salt Lake City, Utah, USA
    November 23, 2013, 12:32 pm

    I like your answer about the question on other scientist scooping your data, because some time the need of a fresh set of eyes can shed light on what could be a hard analysis to do, as is, too many mistakes have been made on anthropology, because only one person made the determination of what they thought of the evidence, and what I mean to say is that because there are so many variables to the evidence, that your concern should be as to what is more important any assessment or the right assessment of the evidence, no matter where it comes from, because close enough is not always good enough.

  7. Gretchen D.
    Berkeley, CA
    November 21, 2013, 1:33 pm

    It’s fascinating to get a look into how this work is being done, and also into the culture – past, present, and maybe future – of paleoanthropology. As a non-scientist, I appreciate the way that you’re making the information you have accessible and intelligible to people like me.

  8. Steve M
    Santa Cruz, CA
    November 21, 2013, 2:15 am

    Nice post John, thank you. Here are a couple of questions that you may be able to answer sooner than later. If the bones are down 30 meters through an 18 cm opening, were they carried there by carnivores, or did they fall from decaying bodies higher up in the cave? Are you finding non-hominin bones in the mix? So far everyone’s talked about hominin fossils, but I would guess there are other bones present as well. Also at 58 seconds into the video about the cavers posted on Nov 15th, there’s a shot of the cave floor littered with bones. Is that the area you’re excavating at the present? One last thing. How about posting map of the cave so we can get a better idea of exactly where the bones lie. Thanks much.