blame colombus? new skeletal evidence and the...

Fertility: the regulator of demographic dynamics in the Ancient Americas 1

Blame Blame ColombusColombus? New skeletal ? New skeletal evidence and the evidence and the paleodemographypaleodemographyof the Americas over the millennia.of the Americas over the millennia.

FertilityFertility: : regulator of demographic dynamics in the regulator of demographic dynamics in the

Ancient AmericasAncient Americas

paper posted at: paper posted at: www.hist.umn.eduwww.hist.umn.edu//~~rmccaa/paleodem.docrmccaa/paleodem.doc


Machu Picchu Machu Picchu (Peru):(Peru):

Royal sanctuaryRoyal sanctuary(Virgins of the Sun??),(Virgins of the Sun??),

microclimate microclimate archipelago, archipelago,

World Heritage World Heritage Site, &Site, &……


excellent excellent paleodemographypaleodemography

laboratory: laboratory: 107 107

burial caves,burial caves,13501350--15501550

(Incas were (Incas were mummified and mummified and

worshipped; none worshipped; none buried, not even buried, not even

at Machu Picchu)at Machu Picchu)


Inca Roads, Inca Roads, ~1500:~1500:

Quito (Ecuador) Quito (Ecuador) to Cuzco (Peru) to Cuzco (Peru)

and Santiago and Santiago (Chile)(Chile)

((areas studied are areas studied are marked by hatchingmarked by hatching))


Location of Location of Machu Picchu Machu Picchu and Inca roadsand Inca roads


Remains of Inca Roads, Remains of Inca Roads, near near HuanacoHuanaco (inland from Lima)(inland from Lima)


Inca Road Inca Road leading to leading to

Machu Machu PicchuPicchu


Machu Machu Picchu Picchu 2570 2570

metersmetersabove seaabove sea

levellevel


Hikers climb a Hikers climb a steep section on steep section on

the the OllantaytamboOllantaytambo--Machu Picchu Machu Picchu

TrailTrail(fourth and final (fourth and final

day)day)



Sacred Plaza of Sacred Plaza of Machu Picchu after Machu Picchu after

clearing in 1912 clearing in 1912 (Hiram Bingham (Hiram Bingham

expedition)expedition)



Machu PicchuMachu PicchuTerracing faces Terracing faces North to catch North to catch the sunthe sun’’s rayss rays


Richard Richard SteckelSteckel and Jerome Rose and Jerome Rose (eds.), (eds.), The Backbone of History: The Backbone of History: Health and Nutrition in the Western Health and Nutrition in the Western HemisphereHemisphere (7000 BP (7000 BP –– 1900 AD), 1900 AD), Cambridge University Press, 2002Cambridge University Press, 2002

•• Largest collection of skeletal Largest collection of skeletal microdata ever assembled: 12,500 microdata ever assembled: 12,500 skeletons, 65 sites, 7 millennia skeletons, 65 sites, 7 millennia

•• Uniform methodology: 24 bioUniform methodology: 24 bio--archaeologists, 6 historiansarchaeologists, 6 historians


Subject:Subject:The human The human skeleton.skeleton.

Microdata:sourceMicrodata:sourcefor studying for studying health, nutrition health, nutrition and demographic and demographic dynamicsdynamics


One of the best preserved, most One of the best preserved, most complete skeletons at Machu Picchucomplete skeletons at Machu Picchu


Outline (55 slides):Outline (55 slides):•• 1. (20) 1. (20) BioarcheologicalBioarcheological evidence on evidence on paleopathologiespaleopathologies and height: Ancient and height: Ancient America was no paradiseAmerica was no paradise

•• 2. (15) 2. (15) PaleodemographyPaleodemography: new method : new method using model stable populationsusing model stable populations

•• 3. (20) New findings: demographic 3. (20) New findings: demographic dynamics for 3 periods:dynamics for 3 periods:Ancient (7000 Ancient (7000 –– 1500 BP)1500 BP)Classic (1500 Classic (1500 –– 500 BP)500 BP)Historical (500 Historical (500 –– 100 BP)100 BP)


Blame Columbus? Blame Columbus? (Title of a (Title of a New York TimesNew York Times review of book, review of book,

but not a concern of the book itself)but not a concern of the book itself)•• 1. 1. BioarcheologicalBioarcheological evidence on evidence on paleopathologiespaleopathologies and height: and height: Ancient America was no paradiseAncient America was no paradise

•• 2. 2. PaleodemographyPaleodemography: new method: new method•• 3. Demographic dynamics for 3 3. Demographic dynamics for 3 periods:periods:Ancient (7000 Ancient (7000 –– 1500 BP)1500 BP)Classic (1500 Classic (1500 –– 500 BP)500 BP)Historical (500 Historical (500 –– 100 BP)100 BP)


4 measures of health and nutrition4 measures of health and nutrition

1.1. PoroticPorotic hyperostosishyperostosis2.2. Degenerative joint disease (limbs, Degenerative joint disease (limbs,

spine)spine)3.3. Dental diseaseDental disease4.4. Stature Stature


1. Hard Times in Ancient Americas1. Hard Times in Ancient Americas»» Skeletal Skeletal archaeology archaeology shows shows poroticporotichyperostosis hyperostosis as nearly as nearly universal universal ——perhaps due perhaps due to extreme to extreme dependence on dependence on corn. corn.


PoroticPorotic Hyperostosis: Hyperostosis: a physiological adaptation to a physiological adaptation to

inadequate absorption of oxygeninadequate absorption of oxygen•• High frequency: 1/3 High frequency: 1/3 –– 1/12 of adults in 1/12 of adults in these communities show signs of these communities show signs of extraordinary bone remodeling. extraordinary bone remodeling.

•• Worsened over time: as the transition to Worsened over time: as the transition to sedentary agriculture proceeded (1sedentary agriculture proceeded (1--3,000 3,000 BP), physiological conditions deteriorated. BP), physiological conditions deteriorated.

•• No gendered difference: No gendered difference: ““A near A near complete absence of sex differentials in complete absence of sex differentials in pathologies is surprising.pathologies is surprising.””


Mild, healed Mild, healed poroticporotic hyperostosishyperostosis


2.Degenerative joint disease (DJD)2.Degenerative joint disease (DJD)•• DJD: 10DJD: 10--20% of adults of both sexes.20% of adults of both sexes.•• From age 20, hard, repetitive work exacted From age 20, hard, repetitive work exacted

severe wear on both sexes, particularly of joints severe wear on both sexes, particularly of joints required for mobility, manipulation of objects, required for mobility, manipulation of objects, and and carrying carrying loads.loads.

•• GenderGenderdifferences:differences:statisticallystatisticallysignificantsignificantin DJD andin DJD andcranialcranialfractures. fractures.


Degenerative joint disease, Degenerative joint disease, spinespine::picture worsenspicture worsens

•• Generally high levels ranging from 25 to Generally high levels ranging from 25 to 83% for adults from the Mesoamerican 83% for adults from the Mesoamerican sitessites——a ubiquitous affliction, principally a ubiquitous affliction, principally due to hard labor. due to hard labor.

•• ““Where the means of carrying heavy Where the means of carrying heavy burdens is almost solely the human body, burdens is almost solely the human body, an enormous biological cost is exacted an enormous biological cost is exacted from the organism.from the organism.””


3. 3. Severe Severe dental dental disease disease

was was common common

in in societies societies based on based on

corncorn


Enamel Enamel HypoplasiasHypoplasias


Shovel Shovel shaped shaped incisors:incisors:geneticgenetictrait of trait of Native Native

AmericansAmericans


Stature in Stature in ““MexicoMexico””, over past , over past 5000 years: 3 features stand out5000 years: 3 features stand out

•• 1. Males decline over time in mean 1. Males decline over time in mean height: 1 cm. per thousand yearsheight: 1 cm. per thousand years----due to worsening nutrition?due to worsening nutrition?

•• 2. Female stature constant over 2. Female stature constant over time even from pretime even from pre--historic period. historic period.

•• 3. Males show decreasing stature 3. Males show decreasing stature from north (164 cm) to south (161 from north (164 cm) to south (161 cm). cm).


Male stature declines over time: Male stature declines over time: confirmed in Center and Southconfirmed in Center and South

Fig. 1. Change in Stature by Region: Mexican MalesYears Before Present

cent

imet

ers

NorthR**2= .04 b=-.0006 P>.59 mean=164.7

-5000 -2000 -1500 -750 -100

150

160

170

Yaqui

TarahumaCora

CuliacanPericu

Tecualil

RVerdetc

CandelarCandelar

V Reyes

cm

SouthR**2= .63 b=-.0036 P<.01 mean=160.7

-5000 -2000 -1500 -750 -100

150

160

170

MChiapasMYucatan

Tsotzil

Zapotec

Tzeltal

Zaculeu

PlayaCar

Altar

Can Cun

Coixtlah

Altar

M Alban

ZaculeuTikal

ChiapaCo

Jaina

Tikal

Altar

Dzibietc

ChiapaCo

Monte Ne

cent

imet

ers

CenterR**2= .53 b=-.0014 P<.01 mean=162.3

-5000 -2000 -1500 -750 -100

150

160

170

OtomiTotonac

TarascanNahuaTeotihuaBasin

Tehuacan

Teotihua

Tlatilco

Tehuacan

CuicuilcChupicuaTicoman

Tecolote

Tehuacan

cm

All RegionsR**2= .23 b=-.0014 P<.01 mean=162.1

-5000 -2000 -1500 -750 -100

150

160

170

OtomiTotonac

MChiapas

Yaqui

Tarahuma

MYucatan

Cora

Tsotzil

TarascanZapotecNahua

Tzeltal

Teotihua

CuliacanPericu

Zaculeu

PlayaCar

Altar

Tecualil

Basin

RVerdetcTehuacanCandelarCan Cun

Candelar

Coixtlah

Altar

M Alban

ZaculeuTeotihuaTikal

ChiapaCo

V Reyes

Jaina

Tlatilco

Tehuacan

CuicuilcTikal

Altar

ChupicuaDzibietc

ChiapaCo

Monte Ne

TicomanTecolote

Tehuacan

North North ⌦⌦=16=165 cm 5 cm ““nono”” declinedecline

South South ⌦⌦=16=161 cm 1 cm much declinemuch decline

CenterCenter⌦⌦=16=162 cm 2 cm some declinesome decline

All All ⌦⌦=162 c=162 cm m accelerating accelerating declinedecline


Fig. 1. Stature of Mexican Males in Time and SpaceDegrees North

cm

Pre-Classic (3200-1800 BP)R**2=.12 b=-.25 P>.32 mean=163.9

15 20 25 30

150

170

DzibietcChupicua

Ticoman

CuicuilcTlatilco

Tehuacan

Monte Ne

ChiapaCo

Altar

Tikal

cm

Classic (1800-1200 BP)R**2=.36 b=.5 P>.11 mean=161.8

15 20 25 30

150

170

TikalAltarZaculeu

ChiapaCo

M Alban

Jaina Teotihua

V Reyes

cm

Post-Classic (1200-500 BP)R**2=.47 b=.36 P<.01 mean=162.8

15 20 25 30

150

170

ZaculeuAltar

Coixtlah

PlayaCarTehuacan

Can Cun

TeotihuaBasin

RVerdetc

Tecualil

CuliacanPericuCandelar

Candelar

cm

Modern (100-40 BP)R**2=.74 b=.78 P<.01 mean=159.2

15 20 25 30

150

170

TzeltalMChiapas

Tsotzil

Zapotec Nahua Tarascan

TotonacOtomi

MYucatan

Cora

Yaqui

Tarahuma

Male stature gradient S. (15Male stature gradient S. (15°°) to N. (30) to N. (30°°): ): greatest in modern times (1900greatest in modern times (1900--1960)1960)

32003200--1800 BP 1800 BP ⌦⌦=164=164 cm cm b=b=--.25, r.25, r22=.12=.12

18001800--1200 BP 1200 BP ⌦⌦=16=162 cm 2 cm b=.50, b=.50, rr22=.36=.36

12001200--500 BP500 BP⌦⌦=163=163 cm cm b=.36, b=.36, rr22=.47=.47

100100--40 BP 40 BP ⌦⌦=159 c=159 cm m b=.78, b=.78, rr22=.74=.74

Females (<150 cm, 5Females (<150 cm, 5’’) little variation in space or ) little variation in space or time. Machu Picchu = 4time. Machu Picchu = 4’’ 1111””; males = 5; males = 5’’ 22””

S. S. N. N.

S. S. N. N.


PrehispanicTerracingPrehispanicTerracing in in CholcaCholcaValley (Peru): conserves water and Valley (Peru): conserves water and

sunlightsunlight


Ancient and Ancient and modern terracing: modern terracing:

OllantaytamboOllantaytambo(Peru)(Peru)


Inca Inca terracing terracing

and and irrigationirrigation

(from (from GuamanGuamanPomaPoma, , La La

nuevanuevacrcróónicanica,,

1615)1615)


Planting Planting potatoespotatoes

(however, (however, 2/3 of diet 2/3 of diet at Machu at Machu

Picchu Picchu consisted of consisted of

corn)corn)


raysrays


BlameBlame……??

•• 1. 1. BioarcheologicalBioarcheological evidence on evidence on paleopathologiespaleopathologies and height: Ancient and height: Ancient America was no paradiseAmerica was no paradise

•• 2. 2. PaleodemographyPaleodemography: new method: new method•• 3. Demographic dynamics for 3 periods:3. Demographic dynamics for 3 periods:

Ancient (7000 Ancient (7000 –– 1500 BP)1500 BP)Classic (1500 Classic (1500 –– 500 BP)500 BP)Historical (500 Historical (500 –– 100 BP)100 BP)


PaleodemographyPaleodemographyMaterials:Materials:skeletons by skeletons by estimated age at estimated age at deathdeathMethods:Methods:fit estimated fit estimated age distributionage distributionto stable modelsto stable models


A quick lesson in model life tables A quick lesson in model life tables (of stable populations)(of stable populations)

•• Stable populations: Stable populations: –– regardless of initial conditions, regardless of initial conditions, –– populations subjected to constant birth populations subjected to constant birth and death rates and death rates

–– will evolve to stable age and death will evolve to stable age and death structures. In other words:structures. In other words:•• % population aged 0, 1, 2, % population aged 0, 1, 2, …… will be the will be the same yearsame year--afterafter--year as long as birth & year as long as birth & death rates are stabledeath rates are stable

•• % of deaths aged 0, 1, 2, % of deaths aged 0, 1, 2, …… will be the will be the same yearsame year--afterafter--year year ……


So, for the So, for the paleodemographerpaleodemographer……

•• If ancient populations were stableIf ancient populations were stable•• If the recovered skeletons are If the recovered skeletons are representative of the dying populationrepresentative of the dying population

•• And if the age at death of the And if the age at death of the skeletons can be estimatedskeletons can be estimated……

•• Then, we match observed skeletal age Then, we match observed skeletal age distribution with those of stable distribution with those of stable populations to derive: populations to derive: –– Birth and death ratesBirth and death rates–– Life expectancy, Life expectancy, ……even age structureeven age structure


How exactly do we do this?How exactly do we do this?2 steps: Step 1. 2 steps: Step 1.

Materials: Age distribution of skeletonsMaterials: Age distribution of skeletons•• Example, Example,

Belleville, Belleville, Ontario. Ontario. 1919thth century century white white populationpopulation——skeletonsskeletonswell well preservedpreserved

AgeAge0055101015152020252530303535404045+45+

Deaths (n)Deaths (n)239 239 31 31 12 12 4 4 22 22 11 11 21 21 36 36 31 31

116 116

%%45.7 45.7 5.9 5.9 2.3 2.3 0.8 0.8 4.2 4.2 2.1 2.1 4.0 4.0 6.9 6.9 5.9 5.9 22.122.1

Cum %Cum %45.745.751.651.653.953.954.754.758.958.961.061.065.065.071.971.977.877.8100.0100.0


How exactly do we do this?How exactly do we do this?Step 2. Models: life tablesStep 2. Models: life tables

•• CoaleCoale & & DemenyDemeny 19831983•• 25 e25 e00 tables: 20tables: 20--80 80 years, at 2.5 year years, at 2.5 year intervalsintervals

•• 13 13 GRRsGRRs: 1 : 1 –– 6 girls, at 6 girls, at various intervalsvarious intervals

•• 4 Regions: North, 4 Regions: North, South, East, WestSouth, East, West

•• Total: 25x13x4=Total: 25x13x4=1300 model life tables1300 model life tables


Model West Females Model West Females level 2,GRRs 0.8 level 2,GRRs 0.8 –– 66

ee00 = 22.5 years= 22.5 years•• Statistics:Statistics:

–– Population at/to Population at/to ageage

CummulativeCummulative %%

CummulativeCummulative %%

% Population at age% Population at age

% deaths at age% deaths at age

Other statsOther stats

–– Deaths at/to ageDeaths at/to age–– 18 statistics for 18 statistics for each GRR (see each GRR (see separate pages separate pages for other efor other e00s and s and regions)regions)


ee00=52.5=52.5

ee00=22.5=22.5

Question: Are age structures of dying determined by Question: Are age structures of dying determined by fertility (within a sheet) fertility (within a sheet) or mortality (between sheets)?

Between (mortality)?Between (mortality)?

Answer: contrary to common sense, fertility!!!Answer: contrary to common sense, fertility!!!

or mortality (between sheets)?or mortality (between sheets)?


% of deaths at age 0, 1, … 75with variations in fertility:GRR =2 , 3, 4, 5, 6; e0 = 20

Fertility effects are bigFertility effects are big


Fig. 2. Mortality offers a small target

% of deaths at age 0, 1, … 75with variations in mortality:GRR = 3; e0 = 20, 30, 40, 50

Mortality effects are smallMortality effects are smallexcept at young (< 15) and old ages (70+)except at young (< 15) and old ages (70+)


GRR = 3e0=20, 30, 40, 50

GRR = 4e0=20, 30, 40, 50

GRR = 2, 3, 4, 5, 6e0=20

GRR = 2, 3, 4, 5, 6e0=50


Three recent advances in Three recent advances in paleodemographypaleodemography::

1.1. Fertility has stronger effects on age Fertility has stronger effects on age distributions than mortality.distributions than mortality.

2.2. Proportional hazard models are more Proportional hazard models are more robust than simple percentages.robust than simple percentages.

3.3. Fitting observed skeletal distributions Fitting observed skeletal distributions to stable populations yield valuable to stable populations yield valuable demographic insights.demographic insights.


Four innovations hereFour innovations here1.1. Use only Use only ““bestbest”” age data: ages 5age data: ages 5--4545

2.2. Fit all possible models:Fit all possible models:GRR GRR (gross reproduction ratio)(gross reproduction ratio) = 2= 2--6 daughters6 daughtersee00 (life expectancy at birth)(life expectancy at birth) = 20= 20--50 years50 years

3.3. Consider range of good fits, instead of Consider range of good fits, instead of only only ““best fitbest fit””——all all ““pretty goodpretty good”” fits fits

4.4. Calibrate Calibrate paleodemographicpaleodemographic results results against historical demographyagainst historical demography——see next figuresee next figure


Calibrating method: skeletal data for Calibrating method: skeletal data for 1919thth century Belleville, Ontariocentury Belleville, Ontario

pretty good fits notnot


Better fertility models fit a small spread: GRR=2.9-3.5Better mortality models range too widely: e0=20-50

good

ness

of f

it (p

>)

Fig. 3. Bellville: Many good fitting modelsgross reproduction ratio

2 2.5 3 3.5 4

.05

.5

.95

30 30 50405040 2020 40302020 5030 5040 304020505020 30

30 402040 50

3050

4020


Calibration of life Calibration of life expectancy, eexpectancy, e00 (Belleville)*(Belleville)*

PaleodemographicPaleodemographic ee0 0 = = historicalhistorical--demographic edemographic e00 = 36 years= 36 years

•• Conventional Conventional paleodemographypaleodemography: : 20.8 years (MAD, 20.8 years (MAD, ““mean age at deathmean age at death””))

•• Hazard models, using best age data, pretty Hazard models, using best age data, pretty good fits, GRR = 3.16, growth rate = 2%:good fits, GRR = 3.16, growth rate = 2%:36 years (see table 4.1)36 years (see table 4.1)

•• Historical data (parish books, census)Historical data (parish books, census)36.5 years36.5 years

*thanks to an anonymous reviewer for the idea of calibrating the*thanks to an anonymous reviewer for the idea of calibrating the method method using Belleville.using Belleville.


BlameBlame……??

•• 1. 1. BioarcheologicalBioarcheological evidence on evidence on paleopathologiespaleopathologies and height: and height: Ancient America was no paradiseAncient America was no paradise

•• 2. 2. PaleodemographyPaleodemography: new method: new method•• 3. Demographic dynamics for3. Demographic dynamics for

3 periods:3 periods:Ancient (7000 Ancient (7000 –– 1500 BP)1500 BP)Classic (1500 Classic (1500 –– 500 BP)500 BP)Historical (1500 AD Historical (1500 AD –– 1900)1900)


65 65 sitessites studiedstudied


PaleodemographyPaleodemography: new methods, : new methods, surprising results: Fertility, the keysurprising results: Fertility, the key

Fertility: an important regulator of Fertility: an important regulator of Ancient (and modern) American demographic dynamicsAncient (and modern) American demographic dynamics(TFR = Total Fertility Rate(TFR = Total Fertility Rate——aveave. children per mother) . children per mother)

•• Lowest fertility: ancient times (1500+ BP), TFR=4Lowest fertility: ancient times (1500+ BP), TFR=4--55•• Higher fertility: middle period (1500BP Higher fertility: middle period (1500BP ––1500AD), 1500AD),

TFR= 5TFR= 5--66•• Highest fertility: domesticated animals (horse, Plains Highest fertility: domesticated animals (horse, Plains

Indians, 1500 ADIndians, 1500 AD--1900), TFR=6.41900), TFR=6.4•• Last five hundred years: large ethnic differentials:Last five hundred years: large ethnic differentials:

Native Americans: 5.6Native Americans: 5.6--6.46.4African Americans: 6.2African Americans: 6.2--6.66.6European Americans: 4.8European Americans: 4.8--5.25.2


Time: Ancient, Classic, and post-Columbian Americas

Fig. 4. Fertility increased between ancient and classic erasLittle change between classic and post-Columbian eras

Early, GRR=2.1-2.3;sites: rea osg cot lat lib LNP teo KIT CUI TL2 MR1

p

grr

2 2.5 3 3.5 4

.05

.5

.9530

20

40

50

5020 40

30 302040

505040302040

Classic, GRR=2.8-2.9; sites: LNC QUI co9 cop 101 111 201PEA SUN MON dol J73 CO1 XCA AZ1 3AM CHB SGB Y1B ESB

p

grr

2 2.5 3 3.5 4

.05

.5

.95

4050

305020

2030

40 5050403020

Post-Columbian, GRR= 2.8-2.9;sites: snt 301 303 BUF haw dk2 KX1 CRW DW2 BU2 CHY BFT

p

grr

2 2.5 3 3.5 4

.05

.5

.9550

402030

30 5020

40 50

502040 403020 5030

Fertility surge occurred in Fertility surge occurred in Classic era with transition Classic era with transition to agriculture and settled to agriculture and settled populations populations ……Which came first?Which came first?——surge or transition?surge or transition?


Settlement types: foragers, villagers, and townsfolk

Fig. 5. Village fertility is highest; urban, lowest

Foragers and Fishers, GRR=2.3-2.6;sites: osg LNP 101 111 KIT

p

grr

2 2.5 3 3.5 4

.05

.5

.952030

40 50

20 40302030 5040 50

2030 20304040 50502030 2040 30 5020 4050

Ancient Villagers, GRR=~2.7; sites: rea cot lat lib LNCQUI co9 201 PEA SUN MON dol TL2 AZ1 MR1 3AM CHB SGB Y1B ESB

p

grr

2 2.5 3 3.5 4

.05

.5

.952030

40

50

5020304020 503040

Ancient Urban, GRR=2.2-2.5;sites: cop teo CUI J73 CO1 XCA

p

grr

2 2.5 3 3.5 4

.05

.5

.95 2030

4050

40 5020 302030

4050

20 4030 3020 504020 5030 203040 40


Ethnicity: Native-, European-, and African-Americans

Fig. 6. Fertility of African-Americans was highest; Euros-, lowest

Post-Columbian Native-Americans, GRR= 2.8-2.9;sites: snt 301 303 BUF haw dk2 KX1 CRW DW2 BU2 CHY BFT

p

grr

2 2.5 3 3.5 4

.05

.5

.9550

402030

30 5020

40 50

502040 403020 5030

Free African-Americans, GRR=3.1-3.3: FAB 3C9 3La C41DNote: Data for slave populations were too few to analyze

p

grr

2 2.5 3 3.5 4

.05

.5

.95 403020

50

205030

40403020

20 5030 504020 40302040 50 50

European-Americans, GRR=2.4-2.6;sites: cry ftl GPS stt HPK sfc sfa SF1

p

grr

2 2.5 3 3.5 4

.05

.5

.95

20

30

40 504030 5020

203040 40302050 502030


PaleodemographyPaleodemography: new methods, : new methods, surprising results: Mortality (pooled)surprising results: Mortality (pooled)

Life expectancy estimates, eLife expectancy estimates, e00: : ** requires a good estimate of growth rate **** requires a good estimate of growth rate **

•• Highest eHighest e00: ancient times (1500+ BP), ~34 years: ancient times (1500+ BP), ~34 years

•• Lowest eLowest e00: middle period (1500: middle period (1500--500), ~23 years500), ~23 years

•• Modern: large ethnic differentials in eModern: large ethnic differentials in e00

Native Americans: eNative Americans: e00=~ 22=~ 22--23 years23 yearsAfrican Americans: eAfrican Americans: e00=~ 21=~ 21--29 years29 yearsEuropean Americans: eEuropean Americans: e00=~ 30=~ 30--36 years36 years


Population waves in the Basin of Population waves in the Basin of Mexico, 3500 years ago to presentMexico, 3500 years ago to present

ChristianChristianconquestconquest


Three conclusionsThree conclusions1.1. Great variations in fertilityGreat variations in fertility

•• Ancient timesAncient times,,•• low pressure demographic regime: low pressure demographic regime: •• fertility was a brake on population growthfertility was a brake on population growth

•• Classic timesClassic times,,•• high pressure demographic system: high pressure demographic system: •• higher fertility, low life expectancyhigher fertility, low life expectancy•• mortality was the brake on pop. growthmortality was the brake on pop. growth


Three conclusionsThree conclusions2. Agriculture was the 2. Agriculture was the ““caboosecaboose”” of of

demographic change, not the demographic change, not the ““engineengine””•• Agriculture seems to have evolved as Agriculture seems to have evolved as

a response to demographic pressurea response to demographic pressure•• Rather than propelling demographic Rather than propelling demographic

transformations.transformations.•• Why? Because in classic times Why? Because in classic times

demographic transformations occurred demographic transformations occurred in in allall settlement types. settlement types.


Three conclusionsThree conclusions3. 3. Modern periodModern period: fundamental : fundamental

demography of native peoples did demography of native peoples did not change with the clash of not change with the clash of biospheresbiospheres•• PaleodemographicPaleodemographic method is method is

insensitive to demographic insensitive to demographic catastrophecatastrophe——unless a mass grave is unless a mass grave is foundfound

•• Underlying fundamentals persisted for Underlying fundamentals persisted for almost a thousand years (almost a thousand years (tiltil 1800)1800)


Postscript: Blame Postscript: Blame ColombusColombus? ? 1.1. Demographic catastrophe was realDemographic catastrophe was real——the debate the debate

is about magnitude and cause(s)is about magnitude and cause(s)

2.2. Magnitude: extinction for many smaller Magnitude: extinction for many smaller populations (e.g, populations (e.g, TainosTainos----Hispaniola); 1/3Hispaniola); 1/3--3/4 3/4 loss for larger populations (Aztecsloss for larger populations (Aztecs----Mexico). Mexico).

3.3. Cause(s): the great debateCause(s): the great debate——disease? disease? War/pacification/exploitation? Both?War/pacification/exploitation? Both?

4.4. Varied placeVaried place--toto--place: place: Hispaniola: exploitation, not diseaseHispaniola: exploitation, not disease……


Blame Blame ColombusColombus……????The debate continuesThe debate continues……

see see www.hist.umn.edu/~rmccaa/aha2004www.hist.umn.edu/~rmccaa/aha2004

& 2003 issues of & 2003 issues of RevistaRevista de de IndiasIndias andand Hispanic Hispanic

American Historical ReviewAmerican Historical Review

blame colombus? new skeletal evidence and the...

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