Several readers have expressed skepticism of the high mortality numbers Charles C. Mann reports in his two books in relation to the Columbian Exchange. In case you are not aware, the thesis that Mann outlines is that the primary necessary condition whereby Europeans managed to eliminate indigenous populations from much of the New World was that they brought with them diseases which the native people did not have an immunity to. This model often argues that mortality rates were on the order of 90 percent. Such a scenario has broad plausibility because the situation in the New World has an inverse counterpoint: Africa. Before quinine the European dominion on the continent was limited to outposts and fringes (e.g., the Cape region of South Africa, which was free of many of the diseases deadly to Europeans). Overall I find Mann’s argument qualitatively reasonable, even if one may qualify it on the margins quantitatively. But I stumbled upon more evidence recently: it still holds for those Amerindians which have not been exposed to Eurasian diseases. From a National Geographic story, Into the Amazon:
But violent clashes account for only a fraction of the deaths suffered by native communities at the hands of outsiders. Most died from epidemic diseases, including the common cold, for which they had no biological defenses. Ivan Arapa, one of our scouts, is from the Matis tribe, who were first contacted by the outside world about 25 years ago. Ivan still remembers the wholesale death that accompanied these very first visits of Brazilian government officials to his village.
“Everyone was coughing, everyone was dying,” he recalls. “Many, many Matis died. We didn’t know why.”
More than half of the 350 Matis living along the Ituí River inside the Javari reserve perished in the months following contact, officials say.
It’s a dismal story that’s become all too familiar to Possuelo during his 40-year career as a sertanista, a uniquely Brazilian profession that folds all the skills and passions of a frontiersman, ethnographer, adventurer, and Indian rights activist into a single, eclectic vocation. That’s why our mission is not to make contact with the Flecheiros but rather to gather information on the extent of their territory’s boundaries, information Possuelo will use to bolster his efforts to protect their lands. In other respects, the Flecheiros are to remain, in large measure, a mystery.
Over thousands of years Eurasians, and to a large extent most inhabitants of the “World Island” (Eurasia + Africa), have become habituated to a range of endemic ailments which may make us miserable, but do not kill us. Our bodies are hosts to an order of magnitude more bacteria than our own tissue cells. Most are innocuous or beneficial, but some are potentially deadly. Many of us carry pathogens which do not result in any illness over our lifetimes. There are geneticists who argue that a small minority of people exhibit genetic susceptibilities to pathogens which are normally benign. What if these people are the ancestral type?
I think about this in particular when considering the case of the Sentinel Islanders. This tribe has been left alone by the Indian government, and remains out of contact with the rest of humanity. Some of this is a function that other Andaman Island tribes which have had extensive contact with people from the mainland have not done so well due to the combined effects of Indian disease and diet. But is it right and proper that modern humans be isolated from the rest of the population for their own good? What does the reality of a whole people who are viewed as “Bubble Boys” tell us about the range of the human condition?
Razib Khan’s degrees are in biochemistry and biology. He has blogged about genetics since 2002, previously worked in software development, is an Unz Foundation Junior Fellow and lives in the western US. He loves habaneros.
January 2nd, 2012 at 2:00 am
The problem is that after Europeans and their diseases had spread themselves over the Americas, we have a huge gradient in population density among the survivors – the territory of the former great empires is much more thickly settled than the rest of the area. But Mann’s argument implies that in pre-Columbian times that gradient did not exist, which is implausible. In other words, I am convinced that the decline in population was over 90% throughout the Americas – not that in some places it was over 90% and in others over 99,99%.
January 2nd, 2012 at 2:29 am
The same still holds today for Australian Aborigines who suffer from the combined effects of infectious disease and inadequate medical care, and also for the ‘diseases of civilization’ – see the much higher rate of Type 2 Diabetes for people with Aboriginal ancestry than for the general population, although that is already pretty high and growing.
January 2nd, 2012 at 4:41 am
Razib,
One thing I have always wondered (perhaps you or a commenter would know) is why the Polynesian peoples showed so much susceptibility to Eurasian diseases? They came from Eurasia post-agriculture, after all. In addition they lived in high population densities, usually kept pigs, dogs, or chickens (not just domesticates, but Eurasian ones), and brought along rats with them. Yes, they were semi-isolated from the Eurasian mainland for 3,000-5,000 years, meaning they missed out on later plague episodes, but they should have kept a stronger immune system which should have provided some benefits regardless.
It’s particularly surprising because, judging by modern population densities in the highlands, New Guinea never had a major population crash post-European contact, despite being nearly as cut off from Eurasian diseases up until the last few hundred years.
Perhaps it just comes down to most Polynesian islands not being large enough to maintain population levels allowing diseases to continually mutate to reinfect old vectors. Instead they tended to “burn out” pretty quickly, hence a fairly rapid decline in immune system efficiency (presuming, of course, a productive immune system has downsides in terms of reproductive fitness).
January 2nd, 2012 at 5:13 am
Obvious answer for the Sentinelese would be to ask them, however difficult informed consent might be to arrange.
Sandgroper – UK data (quoted for example in NHS public health guidance) suggests that people of South Asian, African-Caribbean, black African and Chinese descent may also have a higher risk than those of mainly European descent. Odd. Might well be an historical basis for, say, lactose perisitence among Europeans but why a lower risk of Type 2 diabetes?
January 2nd, 2012 at 5:18 am
Razib,
I don’t dispute the fact that Aztec cultures, for example, were decimated with illness that most Europeans had been exposed to. But I thought we had all interacted together when Pangea was still a single continent? So perhaps I would reason that perhaps these virus and and bacterias are relatively new.
January 2nd, 2012 at 5:32 am
“Bacterian shock” was just a piece of the puzzle: more direct violence (outright democide, brutal enslavement), makes the other 99% of it, helping disease, including the “disease” of mass suicide and oath of sterility. That way the Caribbean was quite annihilated and replaced in decades (although, as has been noticed recently, Arawak/Taino blood persists, specially among Boricuas – Puerto Rico was a much less exploited island than the usual).
And the same happened in the areas of low density and mostly hunter-gatherer economy. Was small pox or was the annihilation of the bison or was maybe the genocidal attacks by the likes of Gral. Custer what almost exterminated North American natives? A mix. Without the rest, the peoples of America would have bounced from any epidemic, the same that the peoples of Europe bounced from the Black Death.
As has been mentioned above in many areas of America, specially those which were more intensely Neolithic (wow, Neolithic is not just a black and white choice, go figure!), from Mexico to Bolivia, where population densities were large and conquerors had more of a motivation to keep the population alive and working, Natives survived relatively well, either more or less pure or more or less admixed and assimilated but they survived in any case.
January 2nd, 2012 at 6:38 am
@4 – I’d be guessing in relation to Chinese – they developed agriculture independently, traditional southern Chinese diet is pretty low in sugar and fats, not a lot of protein or fatty meat generally (even Chinese pork is very lean compared to European pork), no dairy at all, and white rice is complex carbohydrate that breaks down fairly slowly. These people seem to exhibit elevated risk for diabetes and high blood pressure when they change to more Western diets, drink a lot of soft drinks (sodas), etc. I know quite a few really very slender Chinese guys who suffer from very high blood pressure, diabetes and, curiously, gout, which seems very prevalent in older males. However, a few of them have told me they inherited high blood pressure from their fathers, who presumably had more traditional diets.
I believe that South Asians naturally have higher body fat %. No clue about the others. Maybe just evidence that people have gone on evolving in geographically quite isolated populations and exhibit different disease frequencies.
The evidence of what happened to Aboriginal people is pretty suggestive, though – after white settlement, a lot of them went pretty fast from being slender hunter gatherers on a low fat low carb diet who spent a lot of their lives walking long distances, to being sedentary beggars living on the fatter parts of sheep, refined flour, biscuits, jam, treacle, black tea with loads of white sugar in it, tobacco and alcohol, and they blew up like balloons, and developed respiratory diseases and diseases of civilisation – no adaptation to the products of agriculture.
There is a movement in Australia for indigenous people to return to more traditional diets in order to try to avoid modern stuff that they are not as well adapted to. No idea how successful that is. That would have to include avoiding tobacco and alcohol, so it could be successful in increasing life expectancy without that meaning anything very complicated though. But the Aboriginal people leading this movement also have a pretty good clue about avoiding sugar and high refined carbs generally.
January 2nd, 2012 at 7:43 am
“There are geneticists who argue that a small minority of people exhibit genetic susceptibilities to pathogens which are normally benign. What if these people are the ancestral type?”
“In most modern human populations, the majority of MHC Ialleles have been acquired by introgression from archaic humans (Neanderthals and Denisovans)”
—Origin and plasticity of MHC I-associated self-peptides (Autoimmune Review, Nov 2011)
“Accumulating evidence indicates that neuronal MHC class I does not simply function in an immune capacity, but is also crucial for normal brain development, neuronal differentiation, synaptic plasticity and even behaviour.”
—Immune signalling in neural development, synaptic plasticity and disease (Nature Reviews Neuroscience, 2004)
January 2nd, 2012 at 7:55 am
I have the impression that the Great Dying after Columbus and Cortez killed 90% of the indigenous population of the Americas and spread fast, within a few decades. But the first colonists in VA and MA seem to have found the native population density to have been fairly high, perhaps maximal within the limits of their technology. So did the Great Dying reach the East Coast and the population rebounded?
January 2nd, 2012 at 8:23 am
Just one of the diseases brought to the new world, small pox, was incredibly adept at wiping out native populations. It would burn through a native population killing over 50% of the population not just once but would return aproximately every forty years and be equally effective on that part of the population that had not been born during the first epidemic. Since it was a pathogen that free range pigs carried as well as humans it meant that Europeans sometimes never even met and therefore never recorded that native civilizations ever existed. I live in the midwest in some of the richest farmland in the world, of course it was once densely populated by native americans. But we have almost no record of them. They were virtually all dead before we ever met them. I browsed Powell’s bookstore in Portland for history books on the midwest indians. Each region had hundreds of books, the east coast, the southeast, the western plains, the southwest, and the west coast, but there were almost none for the agriculturally rich midwest. Pigs released by Desoto in Florida in the early 1500′s had 250 years or up to six waves of small pox to reduce the native population of the midwest to such insignificance that our history books barely record them.
January 2nd, 2012 at 8:26 am
My impression of northeastern North America at the beginning of the 17th century is that it was still being depopulated. The dense forests of New England found by the Puritans were second-generation growth on the agricultural fields of disappeared local groups, while the Iroquoian population of the St. Lawrence valley was destroyed. Virginia’s further south, granted.
January 2nd, 2012 at 8:27 am
With regard to: “But is it right and proper that modern humans be isolated from the rest of the population for their own good? ”
The onsite report reviewed in Wikipedia would certainly seem to indicate that the Sentinel Islanders certainly wish to remain isolated. I cannot see any justification in bringing them the wealth of society – good and bad – in preference to their own.
January 2nd, 2012 at 8:48 am
@Roger Bigod, I imagine that the Eurasian disease epidemics probably burnt out before spreading North from Mexico (geographic barriers and lower population densities), so the great dying would have come shortly after first contact by the English (like the stories of Squanto or Pocahontas).
January 2nd, 2012 at 9:22 am
Does this tie in at all with the Hispanic Paradox? After all, many of the Hispanics living such long and healthy lives in the United States are partly or mostly Amerindian.
January 2nd, 2012 at 12:08 pm
But Mann’s argument implies that in pre-Columbian times that gradient did not exist, which is implausible.
where does mann imply this? i want a specific answer (i have both books so feel free to be precise).
#2, yes. though one issue that obscures is the relatively flexible rules for who gets categorized as “aboriginal” now.
One thing I have always wondered (perhaps you or a commenter would know) is why the Polynesian peoples showed so much susceptibility to Eurasian diseases?
i assume it has to do with population bottlenecks + small populations after expansion which couldn’t incubate many infectious diseases.
It’s particularly surprising because, judging by modern population densities in the highlands, New Guinea never had a major population crash post-European contact, despite being nearly as cut off from Eurasian diseases up until the last few hundred years.
very good point! we do know these people were VERY isolated until recently though.
I don’t dispute the fact that Aztec cultures, for example, were decimated with illness that most Europeans had been exposed to. But I thought we had all interacted together when Pangea was still a single continent? So perhaps I would reason that perhaps these virus and and bacterias are relatively new.
your time scale is off. pangea predated modern human by geological time scales.
As has been mentioned above in many areas of America, specially those which were more intensely Neolithic (wow, Neolithic is not just a black and white choice, go figure!), from Mexico to Bolivia, where population densities were large and conquerors had more of a motivation to keep the population alive and working, Natives survived relatively well, either more or less pure or more or less admixed and assimilated but they survived in any case.
interestingly indios were the majority of inhabitants of new spain until the 18th century according to records i’ve read about. so the rise in proportion of mestizos is relatively recent. why? perhaps more infectious later? the preservation of indian dominance in the highlands of south america has a strong biological conditional, the elevation.
“Accumulating evidence indicates that neuronal MHC class I does not simply function in an immune capacity, but is also crucial for normal brain development, neuronal differentiation, synaptic plasticity and even behaviour.”
if you are implying something about intelligence, note that the genetic architecture is highly polygenic. if you don’t understand what that means about the weight of your inference, don’t comment anymore. it’s getting tiresome.
#9, why not multiple plagues? happened in the old world too. dying, bounce back, dying. as maju noted the main issue with the amerindians is that europeans interposed themselves in the demographic expansion phase, blocked their bounce back.
After all, many of the Hispanics living such long and healthy lives in the United States are partly or mostly Amerindian.
i think some have suggested differences in inflammatory response. form what i recall it is mexicans around the mexican border that show this in particular.
January 2nd, 2012 at 12:45 pm
The question of bringing people into contact with the wonders of modern civilization become bogus when it means they are going to die. The best thing we can do for these people is to avoid all contact with them for as long as we can which isn’t going to be forever. Some are already trading for steel tools though they are as yet at least remove from most sources of contagion.
January 2nd, 2012 at 12:58 pm
“I don’t dispute the fact that Aztec cultures, for example, were decimated with illness that most Europeans had been exposed to. But I thought we had all interacted together when Pangea was still a single continent? So perhaps I would reason that perhaps these virus and and bacterias are relatively new.”
I’m trying to mine out some meaning out of this and am having difficulties. Pangea? The continent that existed 300 million years ago?! Is there something I’m missing here, or did someone mix up their history.
January 2nd, 2012 at 1:26 pm
#17, i think she was confused. hopefully she’ll check wikipedia. don’t you appreciate my restraint?
January 2nd, 2012 at 2:26 pm
> don’t you appreciate my restraint?
or else, you appreciate girls with glasses.
January 2nd, 2012 at 2:58 pm
“More than half of the 350 Matis living along the Ituí River inside the Javari reserve perished in the months following contact, officials say.”
Makes you wonder how fast the original wave might have been coast to coast from the first infection – less than a year?
“New Guinea never had a major population crash post-European contact”
extreme xenophobia as disease firebreak?
January 2nd, 2012 at 5:31 pm
As to New Guinea: The idea that it was only the very recent contact with the Highlands which stopped an epidemic has some merit. However, as you noted in the above post, previously uncontacted tribes in the Amazon are still having great casualty rates even when discovered in the modern era.
If I recall correctly (mostly from my reading of Guns, Germs, & Steel), the highlands have probably had a population numbering in the low millions even before the effects of modern agriculture, nutrition, and medicine filtered in. Thus compared to the Polynesians, they would always have had a large enough, and dense enough, population that diseases could remain endemic to the region, mutate, and reinfect old hosts in the future. Hence the need for heightened immune systems.
Still, this doesn’t explain why they fared better than OTL’s Mesoamericans or Andean peoples. There were clearly some tenuous links to other islands in Indonesia for at least several centuries prior to contact, so presumably plagues should have gotten through if possible. Pigs did make it into the highlands, however, although they never became widespread livestock there, so perhaps Eurasian domesticates + high population densities are enough to cope. Still, given what happened in other parts of the world, one would have expected that pigs would have caused epidemic diseases, largely cleared the highlands, and the Austronesians would have moved in, with dense rice paddies encompassing the highlands (similar to Madagascar) within a millennium.
January 2nd, 2012 at 5:42 pm
Roger Bigod, my recollection is that the first pilgrims in MA found the native population to have been recently decimated by disease. The disease was the result of contact with English fishermen, which is how some of the natives had already learned English.
January 2nd, 2012 at 6:14 pm
New Guinea and the Phillipines native populations had domesticated pigs. Thomas Mann specifically hypothesises that the Phillipines did not experience the same population crash the Amerinds did because they had domesticated pigs and were exposed to their pathogens. Makes me wonder of the ancient loathing of pigs in middle eastern cultures was not without reason, maybe an association was made between disease and pigs there as well.
January 2nd, 2012 at 7:14 pm
Going back to the original story: Explains why my ancestors started grabbing for each other as soon as the ships were tied up… The white people had vaccines in their trousers!
January 2nd, 2012 at 9:11 pm
When evolving resistance to a disease, it seems to me that genes that protect against the disease, but allow continued transmission of virulent forms, would be favored. They’d act to kill individuals not carrying the gene.
January 3rd, 2012 at 1:11 am
Mann depicts the pre-Columbian Amazon as very like Bangladesh in density of settlement – in fact I’m not sure there’s any portion of the Americas he will allow to have been thinly populated.
January 3rd, 2012 at 1:29 am
Mann depicts the pre-Columbian Amazon as very like Bangladesh in density of settlement – in fact I’m not sure there’s any portion of the Americas he will allow to have been thinly populated.
no he doesn’t. i can see where you made up that lie, but i read both books, so i know that’s a gross exaggeration to serve your original point. you made up a fact to buttress your argument, and that’s pretty low. stop lying or i’ll ban you* (or, you can quote directly and that will prevent me from accusing you of lying, as people can use google books/amazon to check the context of your quote).
* any complaint that i’m not being nice will result in banning without any further warning.
January 3rd, 2012 at 7:02 am
“the rise in proportion of mestizos is relatively recent. why?”
Mestizos were important and growingly so since the beginning and, while usually deprived from access to the top ruling positions, they were the actual backbone of the Spanish (or more properly Castilian) Empire.
However after independence there was a period, more towards the end of the 19th century and the beginnings of the 20th century, in which these countries became immigration destinations, not just for Iberians but for many other Europeans (very specially those of Romance language, like Italians or French, but also Germans, Irish, etc.) This is parallel to a great extent to the other industrial migrations to North America, Australia, etc.: lots of dispossessed working class people and ease of long-distance travel, together with lots of “development” projects (colonization and putting into economic profitability of otherwise less exploited lands) caused that.
But in any case the main factor seems to be millions and millions of Europeans wanting to emigrate for (mostly) economic reasons. So the why is rather: why was there so many poor people in Europe, so desperate as to emigrate with great hopes but most uncertain expectations to the “colonies” (many of them already independent, I’m using colony here in the Greek sense of the word: as a colonized or settled place).
“the preservation of indian dominance in the highlands of south america has a strong biological conditional, the elevation”.
If you are born and raised there you have the physical condition. And anyhow that only affects a small area: the Altiplano (mostly West Bolivia), while the persistence of Natives is much more widespread, although often in mixed form. If you’d watched news from Latin America (or read articles with photos) regularly, you’d notice how nearly everybody is largely Indio, and that applies even to countries often considered “white” like Chile, Argentina and such: when you watch the student protests, you do see Spanish phenotypes but you also see many phenotypes that must be mixed.
It’d be obviously very hard for native peoples to survive extensively in their original form after five centuries of Eurocentric racist rule (not “apartheid racist” but “assimilating admixing racist” instead: the Latin way to global domination: make them all “Romans” and discriminate against or simply kill those who resist assimilation). They survived instead (in most cases, there are many exceptions) through the easiest way available: becoming Spanish or Portuguese, now “Latino” they say… I go to the “Latino” shop here in Bilbao and I can buy everything from the Andes and Central America and the shop-owner is surely 90% Native American… that’s how it works.
January 3rd, 2012 at 12:38 pm
I think what Maju is getting at is, what I was also wondering: Are we sure those records are accurate? Were they manipulated for politics, the converse of the American (colonial and republic) example?
January 3rd, 2012 at 12:49 pm
However after independence there was a period, more towards the end of the 19th century and the beginnings of the 20th century, in which these countries became immigration destinations, not just for Iberians but for many other Europeans (very specially those of Romance language, like Italians or French, but also Germans, Irish, etc.) This is parallel to a great extent to the other industrial migrations to North America, Australia, etc.: lots of dispossessed working class people and ease of long-distance travel, together with lots of “development” projects (colonization and putting into economic profitability of otherwise less exploited lands) caused that.
i know all this. this is not as important for what became mexico as with for other nations more strongly affected by ‘whitening’ (e.g., brazil, argentina). again, that’s why i said new spain. that’s evidence in the pattern of admixture you see (i.e., working back from recombination of the ancestral blocks).
If you are born and raised there you have the physical condition. And anyhow that only affects a small area: the Altiplano (mostly West Bolivia), while the persistence of Natives is much more widespread, although often in mixed form. If you’d watched news from Latin America (or read articles with photos) regularly, you’d notice how nearly everybody is largely Indio,and that applies even to countries often considered “white” like Chile, Argentina and such when you watch the student protests, you do see Spanish phenotypes but you also see many phenotypes that must be mixed.
dude, again, why do you treat me like i’m a retard?
http://blogs.discovermagazine.com/gnxp/2009/12/how-argentina-became-white/
the issue with europeans has to do with the inability of women to carry babies to term.
January 3rd, 2012 at 12:51 pm
Are we sure those records are accurate? Were they manipulated for politics, the converse of the American (colonial and republic) example?
this is fair. though the mestizos of mexico are 30-40 percent european. the indigenous do have some european admixture, but it seems weird that indios would have had this in the 18th century.
January 3rd, 2012 at 4:06 pm
In reply to #31, there was a fairly quick creation of a Mestizo elite in Mexico, drawn both from the Aztec nobility and from among the favored city-states that had allied with Cortez. This may have had an enormous demographic impact over time because of immunities both genetic and political that they accrued. Consider the PRI politician Esteban Moctezuma Barragan (and remember the Mexican custom of Patronymic Matronymic – Moctezuma is not his middle name). More info here – http://www.andrewcusack.com/2010/10/24/moctezuma-family/
New Spain was different from both the French and English models in North America, in that far more “gachupines” came for a while, made their fortune and then went home. The mestizo elites continued to try to marry whiter, but this was a slow process. So I think what you had was an immediate infusion of European genes, continuing slow infusion, mostly indirectly, through mixture with the new mestizo elite for several centuries; followed by a period inaugurated with Sor Juana de la Cruz when the Mexican elite began to look away from Spanish models, culminating in the Grito de Dolores and Independence, after which mestizo, ahem, penetration of the country gained momentum.
A cautionary note is that “mestizo” in Mexico has often been defined through language, so it’s hard to know what one is tracking when one talks about mestizo populations in the 18th century.
As to the subject of the blog-post, what I find most surprising about recent post-contact disease is the idea that so few European alleles had reached such a tribe. I have always assumed that ‘contact’ was a bit of a term of art. That such tribes were in contact with other tribes who were in contact with the larger society, and that gene flow wouldn’t have been that inhibited. For that matter, I’d have guessed that disease flow wouldn’t have been that inhibited either. I seem to be wrong. But it does surprise me. It makes me wonder whether there might in fact be something else at work – where gene flow was inhibited by a different disease regime in the Amazon that differentially killed off European alleles.
January 3rd, 2012 at 5:48 pm
“Makes me wonder of the ancient loathing of pigs in middle eastern cultures was not without reason, maybe an association was made between disease and pigs there as well.”
Interesting thought. I doubt it specifically because the first farmers must have wiped themselves out multiple times domesticating pigs, cows, sheep, chickens etc.
The process would likely have repeated at every step of the farming expansion as well – especially if the first farmers created a faster moving pastoralist bow-wave that expanded in front of them.
“the issue with europeans has to do with the inability of women to carry babies to term.”
Same with the Han in Tibet apparently.
January 4th, 2012 at 7:36 am
“dude, again, why do you treat me like i’m a retard?”
Uh? WTF?