Thank an archaeologist for human history on International Archaeology Day!

On Oct. 17, we celebrate International Archaeology Day. Last year, the Houston Museum of Natural Science participated on a large scale for the first time in a long time. This year, we will have our “Second Annual” version of the same. So what is archaeology and who are these characters that practice the art of archaeology anyway?

Ask anyone and they will answer “Indiana Jones!” when asked to name a famous archaeologist. Hollywood and the media in general tend to gravitate to this entertaining, but totally off the mark, representation of what it is to be an archaeologist.


Archaeologists are people who study the past. They do so with one goal in mind: reconstructing what our ancestors were up to. In the end, while we might find broken pottery, stone tools, or more sophisticated or larger artifacts, what really counts is the answer to questions like these: Who made this? Why? How? How long ago was this?

It takes a special person to be an archaeologist. Patience truly is a virtue. Doggedness comes to mind as well. It won’t hurt to be lucky, but having knowledge will guide you to that breakthrough you’ve been looking for. You’ll need willingness to continue learning, going hand-in-hand with the admission that you really don’t know all that much. All of these are good traits to have.

Luck is part of all this, but the insights archaeologists come up with and share with all of us can be a whole lot more interesting and head-scratching than any Indiana Jones movie. In that regard, archaeologists are like time travelers, our contemporaries who bring ancient cultures back to life, sometimes so much so that you can almost feel it and smell it.

Recently, I’ve been reading up on the presence of early humans in what is now called the Amazon rainforest. My perception of the prehistory of this huge area is changing quickly. Yes, there were early settlers in this part of the world. Paleoindians did reach Brazil, Bolivia, Peru, Ecuador and the Guyanas. Our knowledge of these early immigrants in this part of the world is so small compared to what we know of North American Paleoindians. But… all that is changing, thanks to the determined efforts of a handful of archaeologists, the very same people whose work and insights we celebrate on Oct. 17.

Take Dr. Anna Roosevelt, for example. A professor at the University of Illinois in Chicago and a curator at the Field Museum in the same city, Dr. Roosevelt has been investigating early human presence in the Amazon for decades now. The information she and her team have uncovered now point to an Amazon region that was very different thousands of years ago — well before the arrival of the Europeans. It was so different that these Amazonian Paleoindians would have a hard time recognizing the current landscape, just as much as we have a hard time coming to grips with the existence of large, densely populated settlements in many portions of the Amazon.

Marajo Island - location (2)

Map of Brazil, with the location of Marajó Island.

To get to this point, Dr. Roosevelt and her colleagues worked for years in the Amazon, in places like Marajó Island as well as rivers further inland. Marajó, an island the size of Switzerland located at the mouth of the Amazon River, yielded evidence of densely-populated settlements, occupied for centuries. This research took years to complete in circumstances where creature comfort was sometimes a distant notion. It took perseverance as well, as the new data and new interpretations ran counter to older, more established explanations of the prehistory of the region. Research in the interior relied on the willingness of non-archaeologists to share news of interesting finds on private properties. Sadly such willingness is not always forthcoming, resulting in the loss of an unknown quantity of materials all over the world.

Building trust among the locals and upholding that reputation is not easy. One has to be determined, focused and dogged in the pursuit of knowledge. Dr. Roosevelt’s team checked off all these boxes, and came up with cool finds, some on land, some underwater.

Diving in the Xingu River, 2001

Archaeologist Dr. Anna Roosevelt diving in the Xingu River, 2001.

On International Archaeology Day, we pay homage to the work done by people like Dr. Roosevelt. Local archaeologists, professional and avocational, physical anthropologists, and artists who work on facial reconstructions will all be at HMNS. Museum docents will share their insights and enthusiasm about archaeology with hands-on experiences, pointing to the various halls in the museum where archaeology is covered. These include the John P. McGovern Hall of the Americas, the Hall of Ancient Egypt and the section of human evolution in the Morian Hall of Paleontology. The event starts at 10 a.m. and ends at 4 p.m. Dig it!

Genetics and Archaeology: Helping Us Understand the Past

Recently I came across several examples of how genetic information has greatly helped us understand the past. Quite often this data is gathered in the most unexpected places. Consider these examples.

In an article published in December 2009, an international group of scientists addresses the issue of the extinction of North American megafauna traditionally dated some 11,000 years ago. A skeleton of a woolly mammoth on display in a museum never fails to impress us. At the same time, most of us would agree that it is a good thing we don’t have to worry any more about these lumbering giants messing up our evening commute. However, what most of us stop worrying about is when these animals became extinct and why. Most of us, that is, but not all of us. This is where the story of ancient DNA retrieved from perennially frozen soil comes in.

A traditional approach to estimate when and where a species became extinct has been to map and date the last known survivors. The thinking was that knowing when and where the last specimens lived would automatically clue us in as to why they died out. Is this true, however? Do these last known survivors really represent that last ones left standing? Or did we miss them and make wrong assumptions?

Creative Commons License photo credit: rpongsaj

The party line about woolly mammoths was that they survived on remote islands in the far northern regions of Alaska and Siberia, a region referred to as Beringia. That is now old hat. New genetic data tells us a different story. Mammoths may have survived much longer than originally thought in the Alaskan interior. Scratch 13,000 years ago. Now it looks like woolly mammoths may have survived for an additional 2,600 to 3,700 years in parts of Alaska. Mitochondrial DNA was retrieved from perennially frozen soil near Stevens Village in the Yukon Flat. What we have here then is a suggestion that we can establish the presence of certain animals in a region at a certain time in the past. No bones needed. Just animal DNA left behind in the soil and preserved because of the permanent frozen condition of the dirt.

While the researchers were careful to address any shortcomings of their approach (contamination of the soil, migration of more ancient DNA from lower-lying areas to more recent layers closer to the surface), there will be reactions from other members in the scientific community. This may be frustrating to those among us who like to see “the final answer” to questions like these, this dialogue is part of what science is all about. We will have to see if these new results will stand up to the criticism that will come.

As megafauna slowly disappeared from the North American landscape, human settlers were making their presence felt. I have written about the questions of where these earlier migrants into the Americas may have come from. There is very good evidence that the Paleoindians migrated from parts of Asia.

Research into a disease known as multifocal leukoencephalopathy resulted in the discovery of a virus labeled as the “JC virus.”

It turns out that we all have a copy of this virus residing within us. It is harmless to most of us, unless your immune system is compromised. Geneticists studying this virus found that it was remarkably stable and very rarely mutated into a new variety. Moreover, the strain of the JC virus carried by the Navajo today is nearly identical to that carried by the modern inhabitants of Tokyo. The JC virus bolsters an Asian origin theory for the First Americans.

Beringia – Image courtesy of NASA.

As to how Paleoindians arrived into the Americas, genetics can help us focus that picture as well. If one accepts that the Bering Strait was an ancient migration route – and most people have no problem accepting this – then the issue is: exactly what route did they follow? A coastal route and an interior, overland route, often suggested by archaeologists, now both seem to have been used.

North American mitochondrial DNA, collected from contemporary populations, points to two migration routes. In a paper published Jan. 19, 2009, scientists studied various mitochondrial DNA haplogroups, zooming in on two rare groups. One of these (known as D4h3) is found only along the Pacific coast and is mostly in South America, while the second group (X2a) is restricted to northern North America.

The presence of X2a in North America east of the Rocky Mountains may support the idea of an ice-free corridor between two ice sheets covering Canada and parts of the US. Some of the earliest migrants may have followed that route which would have taken them into the Great Plains, where the glacial corridor would have ended. The presence of D4h3 along the Pacific may represent a coastal migration route.

Woolly mammoths leaving their DNA in the soil, viruses carried by all of us and DNA shared through the mother’s family line all help us refine and refute some of the ideas on how the first immigrants arrived in the Americas. I am sure genetics will continue to add to our understanding of this momentous period in human history. Stay tuned.