National Geographic News
An illustration of the Santa Maria unloading.

Christopher Columbus's crew unloads the Santa Maria, which ran aground off the coast of Haiti in 1492.

Illustration by Richard Schlecht, National Geographic

Ker Than

for National Geographic News

Published December 5, 2011

The number of Native Americans quickly shrank by roughly half following European contact about 500 years ago, according to a new genetic study.

The finding supports historical accounts that Europeans triggered a wave of disease, warfare, and enslavement in the New World that had devastating effects for indigenous populations across the Americas.

(Related: "Guns, Germs and Steel—Jared Diamond on Geography as Power.")

Using samples of ancient and modern mitochondrial DNA—which is passed down only from mothers to daughters—the researchers calculated a demographic history for American Indians. (Get an overview of human genetics.)

Based on the data, the team estimates that the Native American population was at an all-time high about 5,000 years ago.

The population then reached a low point about 500 years ago—only a few years after Christopher Columbus arrived in the New World and before extensive European colonization began.

Study co-author Brendan O'Fallon, a population geneticist who conducted the research while at the University of Washington in Seattle, speculates that many of the early casualties may have been due to disease, which "would likely have traveled much faster than the European settlers themselves."

For instance, the Franciscan friar Toribio de Benavente—one of the first Spanish missionaries to arrive in the New World in the early 1500s—wrote that Mexico was initially "extremely full of people, and when the smallpox began to attack the Indians, it became so great a pestilence among them ... that in most provinces more than half the population died."

(Related: "Conquistador Was Deep in U.S.: 'Stunning' Jewelry Find Redraws Route?")

Some historians have questioned whether such effects were restricted to particular cities or regions, but the new study suggests mortality was widespread.

Pinpointing a Recent Native American Decline

The new analysis—published in this week's online early edition of the Proceedings of the National Academy of Sciences—found that modern Native Americans are more genetically similar to one another than those living before European contact. This suggests the population size was reduced sometime in the recent past.

Imagine "selecting two individuals from a very small village and asking them how many generations ago they first shared a common ancestor. It's likely to have not been that long," O'Fallon said.

"On the other hand, if the village is very large, you might have to go back a long way to find a common ancestor."

The results run counter to earlier genetic studies, which found no evidence of a recent population contraction among American Indians.

But those earlier studies did not include ancient DNA, which is crucial for establishing an accurate time line, O'Fallon said.

"One previous study did find a decline in population size among Native Americans but inferred the time of the decrease as around 1,000 to 2,000 years ago, [which is] hard to reconcile with what we know about Native American history," he said.

(Related: "American Indian Sailed to Europe With Vikings?")

Although the new study is based on DNA, the researchers caution that their use of statistical analysis means the findings aren't conclusive and can only suggest that a particular scenario most likely occurred.

"Our methods infer thousands of genealogies," O'Fallon said. "By looking at the bulk properties of all these genealogies we can begin to get a clearer picture of what likely happened."

In addition, the margin of error for the new study is rather large, O'Fallon said, so it's possible the decline happened more recently than 500 years ago.

"I don't think it would rule out European influence at all if the bottleneck happened a bit more recently than 500 years ago," he said.

Instead, a slightly more recent time frame might change "our interpretation [of the early cause of the decline] from disease to other causes such as war, societal disruption, loss of homelands, etc."

A Short-Lived Population Bottleneck?

Despite revealing a dramatic drop, the new study suggests that Native American populations eventually recovered to their predecline levels, likely aided by the development of resistance to European diseases.

Furthermore, the genetic health of the group did not appear to suffer long-term damage.

"Our study did not find a substantial reduction in genetic diversity," O'Fallon said. "The bottleneck was fairly short-lived and, while significant, didn't appear to eliminate many lineages that were present before Europeans arrived."

(Related: "Sixteen Indian Innovations: From Popcorn to Parkas.")

Overall, the new results "are some of the most detailed information scientists have about Native American ancestral population demography based on genetic data," said Quentin Atkinson, an evolutionary anthropologist at the University of Auckland in New Zealand, who was not involved in the study.

Commenting via email, Atkinson called the findings "intriguing and suggestive," but he said more work will be needed to reduce uncertainties in both the estimated magnitude and timing of the population reduction.

2 comments
William Rice
William Rice

The impact of smallpox and other contagions on indigenous populations - originally via the ignorant carelessness of the colonizers - later either through intentional negligence and conscious intent can't be over-estimated. (Plague blankets are a fact of history - a strategy not untried on the European continent itself.) 


The Fransiscan friarToribio de Benavente recorded in the early 1500s (within a generation of European contact) a drop in the indigenous population of over 50%. The conservative estimates of population decline during the 300 years after our European arrival is 90%.

That historical document is mentioned in this well-researched if tentative science article.


This extensive continent-wide surveying of mitochondrial DNA confirms a catastrophic die-off did in fact begin with European contact and spread like a bow-wave before settlement of the continent.  Especially devastating effect both west and south of the Mississippi this is why settlers could stake their claims to vast empty tracts without even a twinge of minimal conscience (they were after all 'good Christian folk' claiming the land if from anyone from 'savage heathen' who 'weren't even using it anyway'). 


Here in British Columbia the wave hit in the late 19th century (both the coastal and inland nations having lived in effective isolation from other native nations and from Europeans to that time). Missionaries and traders recording the catastrophe write of voyages up-coast establishing trade relations with scores of villages - then discovering the same villages to be home only to ghosts the next season. The rare survivor told of the plague that carried off entire healthy ancient and affluent villages. 


There's no guesswork or hyperbole in the history of the North American First Nations Apocalypse. 


In the B.C. interior,  where I grew up and my family pioneered, the fate of the Okanagan Salish was dramatic declining in the single generation after arrival of Europeans to the valley to 1/10th the population at first contact. Another generation and there were only a few families left  - and several decades later the last full blood member of the nation passed on.  My grandparents settled (with the permission of those few families) on the lush bottom land by a year-round creek traditionally used as a gathering way-station on the band's way into and down from the mountain pastures - the mid-point on their trek between seasonal permanent homes. My grandparents followed the same pattern as they drove their herds to summer in the foothills then down to winter in the valley. My grandparents watched first-hand the dwindling of a once vibrant community into that single old man - then, in the 1920s, none at all. The nation lived on by merging with a remnant of a nation in another valley.


Today, in Canada, the United Native Nations has helped to revive, sustain and regrow a new community locally and a new nation of nations across Canada. 



Corn Sloppy
Corn Sloppy

Poorly written article that can't seem to accept that the "Evil Whiteman" did not come and intentionally wipe out the Noble Natives.

As long as you have such biases you will always have writers like this that feel the need to put some strange racial slant on history.

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