ArticlePDF Available

Abstract and Figures

Starting around 50,000 years ago, most large terrestrial animals went extinct in most continents. These extinctions have been attributed either to climatic changes, impacts of human dispersal across the world or a synergy among both. Most studies regarding these extinctions, however, have focused on particular continents or used low-resolution analyses. We used recent advances in fossil dating and past climatic models in a high-resolution quantitative analysis, comparing the explanatory power of the hypotheses at global scale. The timing of human arrival to each region was the best explanation for the extinctions. Climatic effects, where present, were additive rather than synergistic with human arrival. While climatic variation was a contributory cause that helped explaining the process, anthropogenic impacts were the necessary cause that drove it.
Content may be subject to copyright.
Bigger kill than chill: The uneven roles of humans and climate on late
Quaternary megafaunal extinctions
Bernardo B.A. Araujo
, Luiz Gustavo R. Oliveira-Santos
, Matheus S. Lima-Ribeiro
e Alexandre F. Diniz-Filho
, Fernando A.S. Fernandez
orio de Ecologia e Conservaç~
ao de Populaç~
oes, Departamento de Ecologia, Universidade Federal do Rio de Janeiro, C.P. 68020, Rio de Janeiro, RJ,
21941-902, Brazil
orio de Ecologia Te
orica e Síntese, Universidade Federal de Goi
as, C.P. 131, Goi^
ania, GO, 74001-970, Brazil
orio de Ecologia, Departamento de Ecologia, Centro de Ci^
encias Biol
ogicas, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS, Brazil
Human impacts
Starting around 50,000 years ago, most large terrestrial animals went extinct in most continents. These
extinctions have been attributed either to climatic changes, impacts of human dispersal across the world
or a synergy among both. Most studies regarding these extinctions, however, have focused on particular
continents or used low-resolution analyses. We used recent advances in fossil dating and past climatic
models in a high-resolution quantitative analysis, comparing the explanatory power of the hypotheses at
global scale. The timing of human arrival to each region was the best explanation for the extinctions.
Climatic effects, where present, were additive rather than synergistic with human arrival. While climatic
variation was a contributory cause that helped explaining the process, anthropogenic impacts were the
necessary cause that drove it.
©2015 Elsevier Ltd and INQUA. All rights reserved.
1. Introduction
Since the 19th century, when science became aware of the
sudden and geologically recent disappearance of many large-
bodied animals, the late Quaternary Extinctions (LQE) have
remained a great and controversial matter (Grayson, 2008). Start-
ing around 50,000 years ago, about two thirds of all large terrestrial
animal genera went extinct in a sequence that affected most con-
tinents (Koch and Barnosky, 2006). For a long time, two main hy-
potheses eattributing these extinctions either to climatic changes
during the last glacial event or to the impacts of modern man's
dispersal across the world ehave divided the academic commu-
nity. Many researchers also came to defend a synergy between both
factors as a more plausible scenario for the extinctions (Barnosky,
2004; Nogu
es-Bravo et al., 2008; Lorenzen et al., 2011; Prescott
et al., 2012; Lima-Ribeiro and Diniz-Filho, 2013), although contro-
versies about the balance of climate and humans as extinction
drivers still remain (Lima-Ribeiro et al., 2012; Prescott et al., 2012).
The late Quaternary megafaunal extinctions were a global
phenomenon and we believe that a global approach is the best way
to understand causal mechanisms. This would bring the full range
of temporal and geographical variation in extinction times to bear,
allowing one to disentangle the overall signal from regional trends.
Most studies, however, have focused on particular continents and
taxa (e.g. Alroy, 2001; Diniz-Filho, 2004; Johnson, 2006; Nogu
Bravo et al., 2008). A few global analyses have been presented
(Lyons et al., 2004; Gillespie, 2008; Prescott et al., 2012; Sandom
et al., 2014); but innovative and insightful as these studies have
been, they carry some problems. While some works lack quanti-
tative analyses of the proposed extinction causes (e.g. Lyons et al.,
2004; Gillespie, 2008), others are based on crude and often unre-
alistic scenarios of human arrival and megafaunal extinction
(Prescott et al., 2012; see Lima-Ribeiro et al., 2012 for details). Both
Prescott et al. (2012) and Sandom et al. (2014) include non-
quantitative variables in their models, as their hominin paleoge-
ography variable is based on discrete human arrival scenarios. The
most recent global analysis (Sandom et al., 2014) is based on global
databases on extinct (and extant) mammals' distributions that are
bound to be incomplete and/or to contain a proportion of un-
trustworthy data (as shown by the inclusion on the analysis
of Africa and Southern Asia, regions with poor paleontological
*Corresponding author.
E-mail address: (B.B.A. Araujo).
orio de Macroecologia, Universidade Federal de Goi
as, Campus Jataí,
75804-020, Jataí, GO, Brazil.
Contents lists available at ScienceDirect
Quaternary International
journal homepage:
1040-6182/©2015 Elsevier Ltd and INQUA. All rights reserved.
Quaternary International 431 (2017) 216e222
records). Additionally, their approach lacks a comparison of
extinction dates with human arrival and climatic change focused on
chronology (rather than geography).
Fossil dating allows the establishment of synchrony between
extinction events and their potential drivers. In the last years, a
growing number of dates have been published and reviewed
around the world (see Supplementary References). Improved cli-
matic models have been developed for the last 122,500 years
(Andersen et al., 2004). These advances made a once unfeasible
chronological global analysis of climatic changes, human arrival to
each region and extinction of megafaunal taxa a concrete possi-
bility, opening a promising path for resolving the extinction debate.
In light of these new chronometric advances, we performed an
exhaustive gathering of data for human rst appearance dates
(HFADs) and last appearance of megafaunal genera (MLADs) on
nineteen regions across the globe, together with climatic variation
through the late Quaternary, to provide the rst high-resolution
chronological analysis of the LQE extinctions. We tested the hy-
potheses that human arrival or climate variance would be
responsible for the extinction of megafaunal genera. This more
detailed approach should advance the extinction debate, providing
the rst quantitative chronological test of the roles of anthropo-
genic impacts and climatic variation on the demise of the world's
2. Materials and methods
2.1. Data
The predictions of both hypotheses were compared in order to
evaluate them. The environmental hypothesis predicts that ex-
tinctions would have occurred during or following intense climatic
changes through the late Quaternary. The human impact hypoth-
esis, on the other hand, predicts that extinctions would have fol-
lowed human colonization of each landmass across the planet.
First, last appearance dates of megafauna (MLADs) species and
rst appearance dates of anatomically modern humans (HFADs)
on several landmasses were gathered from all published scientic
sources that could be assessed (see Supplementary Tables 1 and
2). These landmasses included South America, North America,
Caribbean islands, Northern and Western Eurasia, Australia, Tas-
mania, Madagascar, New Zealand and Japan. Climate variation in
the North hemisphere through the last millennia of the Quater-
nary was assessed by the North Greenland Ice Core Project
(NGRIP) data on the variation of oxygen isotopic composition in
ice cores (Andersen et al., 2004). This database comprises
data from the last 122,500 years, with
O values for every 50
years. For the South hemisphere we used the European Project for
Ice Coring in Antarctica (EPICA) database, which comprises data
on the variation of deuterium concentrations (
H) at irregular
but frequent intervals along the last 800,0 00 years. We used EPICA
data for the last 122,500 years only, to cover an interval similar to
the one provided by NGRIP. Both
H are proxies for
temperature conditions for their respective hemispheres. Their
use in our analysis assumes that although changes along the
glacial cycle differed among regions, times of intense global
temperature variation within each hemisphere would be reected
as regional changes of increased magnitude (Walker, 2005). We
opted for this approach, instead of assuming any ner regionali-
zation, because actual global reconstructions of past climatic
conditions are few and punctual across time, and do not neces-
sarily reect periods when megafaunal extinctions took place.
Environmental proxies with high spatial resolution, including
phytophysiognomical reconstructions based on pollen data, are
available for just a few regions across the world, which precludes
their use in global models (Gill et al., 2009, 2013; Rule et al., 2012).
Considering such limitations, we believe that high-resolution
chronological data for each hemisphere can be more informative
than a crude and possibly misleading interpolation of past cli-
matic scenarios in a geological period when climate undergone
many rapid changes.
To allow comparisons between the hypotheses' predictions,
data reliability was assessed through a scoring system. Paleonto-
logical and archaeological dates are sensitive to methodological
errors (Walker, 2005). Sample contamination, poor materials,
stratigraphic misinterpretations, inadequate dating methods and
other problems can seriously jeopardize a date's accuracy. To
identify reliable data, many authors have used different quanti-
tative scales based mainly on sample material, stratigraphic as-
sociations and the type of equipment and logistics used in a given
study (Mead an d Meltzer, 1984;Burney et al., 2004; Barnosky and
Lindsey, 2010; Iwase et al., 2012). Dates from articles and books
that passed through such scrutiny were collected without further
appraisal. In most cases, however, dates lacked any sort of accu-
racy determination, making data ltering a necessity. For radio-
carbon based dates, this ltering was achieved using the Mead-
Meltzer Scale (Mead and Meltzer, 1984)modied by Barnosky
and Lindsey (2010), applying strict criteria: for paleontological
and archaeological dates to be accepted, they had to reach at least
ranks 11 (out of a maximum rank of 12) and 13 (out of a maximum
rank of 17) respectively (following Barnosky and Lindsey, 2010).
Still, most datings performed in Oceania over the extinctions
period are based on different methods, mainly U/Th (Uraniume-
Thorium dating), OSL (Optically Stimulated Luminescence dating)
and ESR (Electron Spin Resonance dating). As there are no scoring
systems capable of evaluating the accuracy of dates obtained by
these methods, ranked scales along the lines of the Mead-Meltzer
Scale were designed to assess the reliability of U/Th and OSL dates
(Supplementary Table 3). The new scales do not include ranks
associated with archaeological remains, because human dates
were always based on radiocarbon methods. ESR dating involves a
more complex set of techniques, making its dates harder to tinto
a simple scoring system. So, only sources that utilized CSUS-ESR
(Closed System U-Series ESR), a more accurate variant of the
ESR method, were considered in the following analyses (Grün
et al., 2008, 2010).
After the data ltering, date calibration was performed. Radio-
carbon datings are based on the
C ratio of tested samples; as
base concentrations of both isotopes uctuate through time in the
atmosphere, calibration is necessary to transform radiocarbon
yearson actual years before present. Dates were calibrated using
the software Calib 6.0, using the IntCal09 curve for every sample.
Even though this calibration curve was originally designed for the
northern hemisphere, it is the only one that encompasses the
whole span of the extinction event.
As a last precaution, we tested bootstrapping corrections over
the paleontological dates of South America (using the Cueva del
Milodon, in Argentina, as the well sampled site) to avoid possible
biases caused by the Signor-Lipps effect, following the methodol-
ogy established by Barnosky and Lindsey (2010). This method has
been criticized by Johnson et al. (2013) for not accounting
adequately for the uncertainties and biases that affect the estima-
tion of MLAD and HFAD. Regarding the nature of the expected bias,
using uncorrected MLAD and HFAD would underestimate the
coexistence between humans and megafauna. Anyway, the use of
corrected data did not signicantly affect the results, thus we opted
for using uncorrected data to perform all analyses described in the
following section, keeping in mind that this could make our ana-
lyses conservative against nding an association between human
arrival and megafaunal extinction.
B.B.A. Araujo et al. / Quaternary International 431 (2017) 216e222 217
2.2. Statistical analysis
All analyses were based on genera rather than species to avoid
taxonomical noise, because fossils are not always identied to the
specic level or such identications are often controversial. As both
times of megafauna extinctions and human colonization vary
considerably within large landmasses, the world was divided into
19 regions. These divisions were based mainly on great geograph-
ical barriers (e.g. Andes, Ural Mountains etc.) and temporal gaps on
human arrival (e.g. Mediterranean vs. northern Europe, islands vs.
adjacent landmasses) (Fig. 1). The time of human arrival was set by
the HFADs in each region, whereas the time of extinctions was set
by the MLADs of each megafaunal genus. The climate changes were
estimated based on
O and
H, as proxies for temperature
variation for the North and the South hemisphere respectively, as
described above. Finally, the relative importance of human arrival
and climate changes on LQE was assessed in two ways.
First, we created two sets of null models, one of climate changes
and another of human arrival, to investigate the chronological as-
sociation of periods of intense climatic change and of HFADs with
the MLADs. For the each hypothesis, a thousand dates were
randomly drawn from the 122,500 years of climatic data available
for each extinct genus on each region. In respect to the climatic
hypothesis, each true last appearance date had the
H vari-
ance calculated for the time interval comprising its dating error
plus another thousand years into the past. This same time span
(true dating error plus a thousand years) was used to calculate the
H variance of all generated random dates. This step assumes
that the effects of climatic changes on regional megafaunal ex-
tinctions would be apparent within a 1000 years interval; this we
regard as a conservative approach to accommodate a delayed
response by the extinct genera. Anyhow, we repeated this proce-
dure using 3000 years intervals and the results remained almost
unaltered. We then estimated the level of signicance of climatic
Fig. 1. (A) The diaspora of modern man through the planet, showing the 19 regions in which the world wasdivided for this study. Arrows indicate the approximate direction of each
major colonization event. (B) The extinction of megafaunal genera at different parts of the world, according to calibrated reliable dates. Points are slightly jittered to minimize
overlap. The color scales indicate the timing of human arrival and extinctions in each place, from the oldest (cold colors) to the most recent (hot colors).
B.B.A. Araujo et al. / Quaternary International 431 (2017) 216e222218
effects on each megafaunal genus in each region by considering the
proportion of random variances equal to or greater than that based
on true MLADs. This metric of climatic instability was chosen as the
environmental variable rather than extreme values because there is
only a single apex to the last glaciation(or two, if the Younger Dryas
is considered), thus climatic variance would be a better candidate
than climatic extremes as a predictor for the extinctions.
A similar method was employed to assess the second hypoth-
esis, only this time the chronological distance between each date
(random or true) and the corresponding regional HFAD was
measured. We then estimated the level of signicance of anthro-
pogenic effect on each megafaunal genus in each region by
considering the proportion of random chronological distances
equal to or lesser than that based on true dates. On every occasion
where the climatic or anthropogenic effects were statistically sig-
nicant ei.e. when extinctions were more closely related to cli-
matic changes or to human arrival than expected by chance ethat
specic cause was considered responsible for the extinction of a
given megafauna genus. When both hypotheses showed signicant
p-values, the result was considered entangled, meaning that the
models could not discern between causes for that particular
extinction event.
In a second approach, we used a generalized linear mixed model
(GLMM) to test, in a single model, the effects of both climate
changes and human arrival (xed effects) on the extinction rates of
megafauna genera, as well as the effect of the interaction between
these hypothesized explanatory variables. As somegenera survived
several millennia after most of their concurrent taxa, to avoid ef-
fects of time-lags between the change of state of a given variable
(human arrival or climatic instability) and total megafaunal demise
within a region, 25% of the most recent extinction dates from every
region were removed from the generalized linear mixed models.
Within each region, the last 60 thousand years of data were divided
into bins of 41 different sizes, ranging from 1000 to 5000 years with
100 year increments. The number of extinct genera recorded in
each bin was obtained; therefore bins were our sample units. The
use of bins of different sizes allowed us to evaluate the robustness
of the results to variations in size, which is an arbitrary choice. The
time since human arrived in each region (the rst explanatory
variable) was measured as the amount of years from the beginning
of each bin to the true HFAD on that region. The climate change (the
second explanatory variable) was quantied as
H variance
within each bin.
The GLMM models were tted using a Poisson distribution
because the number of extinct genera in each bin is a typical
discrete count variable. The regions' identities were included in the
models as random effects (allowing random intercept estimation)
and temporal autocorrelation was controlled between successive
bins within each region using a rst-order autoregressive correla-
tion structure. The models were validated through the checking of
both normality and absence of temporal autocorrelation of the
residuals. The GLMM and null models were run in R software (R
Core Team, 2012) by using the function glmmPQL from the pack-
age MASS (Venables and Ripley, 2002).
3. Results
A total of 2088 dates for 67 genera of extinct megafauna (58
mammals, 8 birds and 1 reptile) were considered reliable, totalizing
126 independent sampling units across 19 regions (Supplementary
Table 1). Similarly, 762 human dates fullled the reliability re-
quirements, and were used in the analyses (Supplementary
Table 2).
Null models showed that most extinctions (85/126, or 67.4%;
Fig. 2 and Supplementary Table 4) took place around the time of
human arrival in each region, as it can be seen by the close temporal
gap between high-resolution MLADs and HFADs across the globe.
This pattern emerged despite the use of uncorrected dates, which
would underestimate the coexistence between humans and
megafauna. A similar correlation of extinction dates with times of
intense climatic variation did not occur: only 17.5% (22/126) of the
MLADs happened in periods of intense
Among these, only 1.6% (2/126) genera disappeared in periods
linked only to great climatic variance, and not to human arrival. On
the other hand, 65 (51.6%) were closer than expected by chance
only to human arrival. Twenty cases (15.9%) were associated to both
events (entangled). In the remaining 39 cases no association could
be found.
Forty one GLMM models were generated encompassing the
range of time bins between 1000 and 5000 years. If either tem-
perature proxy were used to represent climatic variation for the
whole planet, Antarctic
H detected a stronger climatic effect than
O, but human arrival had the strongest effect in both
cases (see Supplementary Table 5). Adopting our approach of using
each proxy to represent climatic variation in its own hemisphere,
the time of most intense climatic variation was signicantly related
to the extinction of megafauna in only 1 of the 41 bins. In sharp
contrast, the date of human arrival was the best predictor of the
extinction of megafauna, with a signicant effect in 40 of the 41
bins. These models had an average R
of 0.525. In the models
considering the interaction between both factors, the interaction
term was signicant in only 4 of the 41 bins (Supplementary
Table 5). Thus GLMM provided stronger evidence for anthropo-
genic than for climatic effects, and little evidence of a synergistic
action of the two factors.
4. Discussion
Overall, our results indicate that human arrival was a necessary
factor for the extinctions, whereas climate variation was a
contributory one, enhancing regionally the effects of anthropogenic
impacts in additive rather than synergistic ways. This conclusion
builds upon the previous ndings of the previous global analyses by
Prescott et al. (2012) and Sandom et al. (2014), but it rests on a ner
data base and it claries the causal relation between the two fac-
tors. The fact that Africa escaped the strong global extinction
pattern reinforces the interpretation of human-driven causes
because there the necessary cause was missing (Klein, 1984): one
would expect stronger anthropogenic impacts in rst contacts with
faunas without any previous evolutionary contact with Homo sa-
piens (Diamond, 1984). Besides, the interpretation that climate
variation was not a necessary cause for the massive LQE is consis-
tent with the pattern that the Pleistocene accommodated over 30
glacial cycles, many as intense as the Last Glacial Maximum
(Barnosky, 2004; Walker, 2005), all of them with few or no asso-
ciated extinctions (Cione et al., 2003; Barnosky, 2004). It has been
argued that the last glacial cycle would have had a greater variance
of temperature than earlier glacial periods eat least in maximum,
rather than the minimum, temperature ein Sahul (Wroe et al.,
2013), but globally climatic variance was not a strong extinction
predictor in our results.
In relation to previous global analyses, our ndings clarify
regional differences, highlighting the limitations of single-
continent studies to make inferences about the causes of the
global process of LQE. For example, while the anthropogenic signal
was straightforward for Australia and the Americas, strong regional
patterns can be observed when northern Eurasia (except Bering) is
viewed apart from the world. In the sampling units within West
Siberia, Central Russia, Japan and Europe, only two of 28 (7%) ex-
tinctions were associated to human arrival and another two
B.B.A. Araujo et al. / Quaternary International 431 (2017) 216e222 219
extinctions (7%) to climatic variation (the only ones in the analysis),
leaving 24 cases unexplained. On Eurasia, extinctions covered a
longer period than anywhere else, encompassing MLADs from 40 to
10 thousand years ago. Therefore, most of them could not be
explained by cold temperature peaks of the LGM or any stadials.
The colonization of Eurasia was the only moment in human
dispersal when paleolithic humans euntil then, a fully tropical
species ewere forced to move against increasingly colder envi-
ronments as they expanded their populations toward high lati-
tudes. The HFADs from Central Russia and Europe are over 45
thousand years old, about 30 thousand years older than those from
Bering and almost 20 thousand years older than the rst human
Fig. 2. Geographic distribution of the results of the null model investigating the effects of two factors on megafaunal extinctions across the world. P-values in red show cases were
extinctions happened in (a) periods of high climatic variation as expressed by
H concentrations in ice cores and (b) closer than expected by chance to human arrival dates.
Histograms show the distribution of p-values under the two hypotheses. The lower image (c) shows the geographical distribution of cases where the extinctions were better
explained by climatic variations, human arrival, both factors (entangled) and none. Points are slightly jittered to minimize overlap.
B.B.A. Araujo et al. / Quaternary International 431 (2017) 216e222220
dates across the arctic (Pitulko et al., 2004). Accordingly, Surovell
et al. (2009), after correcting for taphonomic bias, found evidence
that mammoths suffered a long process of decline toward extinc-
tion, correlated to increased human densities. Thus, the long pro-
cess of peopling northern Eurasia against the cold gradient may
have allowed a greater temporal gap between HFADs and MLADs,
generating a weaker signal in the null model.
Another possible explanation for why extinctions were slower
in Eurasia is the coexistence of megafauna with early Homo for
several thousand years prior to the arrival of modern humans
(Sandom et al., 2014). H.heidelbergensis and H.neanderthalensis had
been present there for hundreds of thousands of years before the
diaspora of modern humans to Eurasia (Stringer and Andrews,
2005). So, as in Africa, coevolution possibly granted the large ani-
mals a greater resilience to hunting by H.sapiens. One must keep in
mind that the true baseline for the behavior of megafauna at rst
contact with hominids is more likely to be represented by the is-
land naivetyrecorded for vertebrates in historical rst contacts
than by modern behavior of animals that have coexisted with
humans for millennia (Diamond, 1984).
Our work is based on few assumptions, including that biological
impacts of climatic variation would be apparent within one to ve
thousand year intervals (see Materials and methods), and that
humans had signicant interactions with the megafauna. Some
authors have questioned the latter assumption, arguing that co-
incidences of HFADs and MLADs are not enough to establish cau-
sality, and that direct evidence that humans hunted megafauna is
scarce (Grayson and Meltzer, 2003). However, the extinct species
were the demographically most vulnerable ones (Johnson, 2002,
2006), and the frequency and geographical distribution of the
existing humanemegafauna associations are consistent with the
expected given the short coexistence between H.sapiens and large
animals in any given locality (Barnosky, 2004; Surovell and Grund,
5. Conclusion
The present study allowed a widened quantitative perspective
on the relative roles of climate variation and human impacts in the
LQE, with human impacts as a much stronger determinant of the
number of extinct genera than climate variance. The extinction of
hundreds of species across the whole planet is such a complex
process that one could hardly expect a single factor to completely
explain every aspect of it. It is highly likely that causal factors like
human impacts and climate changes both acted, in different ways
in different places, to produce the nal outcome, as our ndings
highlight. However, as recent analyses are making increasingly
clear, this does not necessarily mean that both factors had equal
importance. Many Late Quaternary megafaunal extinctions
occurred in the absence of any relevant climatic change, but
seldom, if ever, they occurred independently from human arrival.
Thus, climatic variations were a contributory cause, which some-
times helped determining where and which species went extinct,
while anthropogenic impacts were the necessary cause, without
which probably nobody would be talking today about the extinc-
tion of the megafauna.
We thank Joaquín Hortal, Leonardo
Avila, Leopoldo Solbeizon,
the late Paul S. Martin, the members of the Laborat
orio de Ecologia
e Conservaç~
ao de Populaç~
oes eUFRJ and the members of the First
Peopling of the Americas UNESCO Symposium at Puebla for dis-
cussions. We also thank Caio Kenup for his help with R program-
ming, and Chris Johnson for his constructive commentaries on the
manuscript. All authors except M.S.L.-R. were supported by per-
sonal grants from CNPq (Conselho Nacional de Desenvolvimento
Cientíco e Tecnol
ogico eBrazil) during this research; M.S.L.-R.
received a graduated fellowship from FAPEG (Fundaç~
ao de
a Pesquisa do Estado de Goi
Appendix A. Supplementary data
Supplementary data related to this article can be found at http://
Alroy, J., 2001. A multispecies overkill simulation of the end-Pleistocene megafaunal
mass extinction. Science 292, 1893e1896.
Andersen, K.K., et al., 2004. High-resolution record of northern hemisphere climate
extending into the last interglacial period. Nature 431, 147e151.
Barnosky, A.D., 2004. Assessing the causes of late Pleistocene extinctions on the
continents. Science 306, 70e75.
Barnosky, A.D., Lindsey, E.L., 2010. Timing of Quaternary megafaunal extinction in
South America in relation to human arrival and climate change. Quaternary
International 217, 10e29.
Burney, D.A., Burney, L.P., Godfrey, L.R., Jungers, W.L., Goodman, S.M., Wright, H.T.,
Jull, A.J.T., 2004. A chronology for late prehistoric Madagascar. Journal of Human
Evolution 47, 25e63.
Cione, A.L., Tonni, E.P., Soibelzon, L., 2003. The broken zig-zag: late Cenozoic large
mammal and tortoise extinction in South America. Revista del Museo Argentino
de Ciencias Naturales 5, 1e19.
Diamond, J.M., 1984. Historic extinction: a Rosetta stone for understanding pre-
historic extinctions. In: Martin, P.S., Klein, R.G. (Eds.), Quaternary Extinctions: a
Prehistoric Revolution. Univ. Arizona Press, Tucson, pp. 824e862.
Diniz-Filho, J.A., 2004. Macroecological analyses support an overkill scenario for
Late Pleistocene extinctions. Brazilian Journal of Biology 64, 407e414 .
Gill, J.A., Williams, J.W., Jackson, S.T., Lininger, K.B., Robinson, G.S., 2009. Pleistocene
megafaunal collapse, novel plant communities, and enhanced re regimes in
North America. Science 326, 1100e1103 .
Gill, J.A., McLauchlan, K.K., Skibbe, A.M., Goring, S., Zirbel, C.R., Williams, J.W., 2013.
Linking abundance of the dung fungus Sporormiella to the density of bison:
implications for assessing grazing by megaherbivores in palaeorecords. Journal
of Ecology 101, 1125e1136 .
Gillespie, R., 2008. Updating Martin's global extinction model. Quaternary Science
Reviews 27, 2522e2529.
Grayson, D.K., 2008. Holocene underkill. Proceedings of the National Academy of
Sciences USA 108, 4077e4078.
Grayson, D.K., Meltzer, D.J., 2003. A requiem for North American overkill. Journal of
Archaeological Sciences 30, 585e593.
Grün, R., Wells, R., Eggins, S., Spooner, N., Aubert, M., Brown, L., Rhodes, E., 2008.
Electron spin resonance dating of South Australian megafauna sites. Australian
Journal of Earth Sciences 55, 917e935.
Grün, R., Eggins, S., Aubert, M., Spooner, N., Pike, A.W.G., Müller, W., 2010. ESR and
U-series analysis of faunal material from Cuddie Springs, NSW, Australia: im-
plications for the timing of the extinction of the Australian megafauna. Qua-
ternary Science Reviews 29, 596e610.
Iwase, A., Hashizume, J., Izuho, M., Takahashi, K., Sato, H., 2012. Timing of mega-
faunal extinction in the Late Pleistocene on the Japanese Archipelago. Quater-
nary International 255, 114e124.
Johnson, C.N., 2002. Determinants of loss of mammal species during the late
Quaternary megafaunaextinctions: life history and ecology, but not body size.
Proceedings of the Royal Society of London B 269, 2221e
Johnson, C.N., 2006. Australia's Mammal Extinctions: a 500 00 Year History. Cam-
bridge Univ. Press, Cambridge.
Johnson, C.N., Bradshaw, C.J.A., Cooper, A., Gillespie, R., Brook, B.W., 2013. Rapid
megafaunal extinction following human arrival throughout the New World.
Quaternary International 308e309, 273e277.
Klein, R.G., 1984. Mammalian extinctions and Stone Age people in Africa. In:
Martin, P.S., Klein, R.G. (Eds.), Quaternary Extinctions: a Prehistoric Revolution.
Univ. Arizona Press, Tucson, pp. 553e573.
Koch, P.L., Barnosky, A.D., 2006. Late Quaternary extinctions: state of the debate.
Annual Review of Ecology, Evolution and Systematics 37, 215e250.
Lima-Ribeiro, M.S., Nogu
es-Bravo, D., Marske, K.A., Fernandez, F.A.S., Araujo, B.,
Diniz-Filho, J.A.F., 2012. Human arrival scenarios have a strong inuence on
interpretations of the late Quaternary extinctions. Proceedings of the National
Academy of Sciences USA 109, E2409eE2410.
Lima-Ribeiro, M.S., Diniz-Filho, J.A., 2013. Modelos Ecol
ogicos e a Extinç~
ao da
Megafauna: Clima e Homem na Am
erica do Sul. Editora Cubo, S~
ao Carlos.
Lorenzen, E.D., et al., 2011. Species-specic responses of late Quaternary megafauna
to climate and humans. Nature 479, 359e365.
Lyons, S.K., Smith, F.A., Brown, J.H., 2004. Of mice, mastodons, and men: human
mediated extinctions on four continents. Evolutionary Ecology Research 6,
B.B.A. Araujo et al. / Quaternary International 431 (2017) 216e222 221
Mead, J.I., Meltzer, D.J., 1984. North American late Quaternary extinctions and the
radiocarbon record. In: Martin, P.S., Klein, R.G. (Eds.), Quaternary Extinctions: a
Prehistoric Revolution. Univ. Arizona Press, Tucson, pp. 441e450.
es-Bravo, D., Rodríguez, J., Hortal, J., Batra, P., Araújo, M.B., 2008. Climate
change, humans, and the extinction of the woolly mammoth. Plos Biology 6,
Pitulko, V.V., Nikolsky, P.A., Girya, E.Yu, Basilyan, A.E., Tumskoy, V.E., Koulakov, S.A.,
Astakhov, S.N., Pavlova, E.Yu, Anisimov, M.A., 2004. The Yana RHS site: humans
in the Arctic before the last glacial maximum. Science 303, 52e56.
Prescott, G.W., Williams, D.R., Balmford, A., Green, R.E., Manica, A., 2012. Quanti-
tative global analysis of the role of climate and people in explaining late Qua-
ternary megafaunal extinctions. Proceedings of the National Academy of
Sciences USA 109, 4527e4531.
R Core Team, 2012. R: a Language and Environment for Statistical Computing.
Foundation for Statistical Computing, Vienna. URL.
Rule, S., Brook, B.W., Haberle, S.G., Turney, C.S.M., Kershaw, A.P., Johnson, C.N., 2012.
The aftermath of megafaunal extinction: ecosystem transformation in Pleisto-
cene Australia. Science 335, 1483e1486.
Sandom, C., Faurby, S., Sandel, B., Svenning, J.-C., 2014. Global late Quaternary
megafauna extinctions linked to humans, not climate change. Proceedings of
the Royal Society B 281, 20133254.
Stringer, C., Andrews, P., 2005. The Complete World of Human Evolution. Thames,
Hudson, New York.
Surovell, T.A., Finley, J.D., Smith, G.M., Brantingham, P.J., Kelly, R., 2009. Correcting
temporal frequency distributions for taphonomic bias. Journal of Archaeological
Science 36, 1715e17 24 .
Surovell, T.A., Grund, B.S., 2012. The associational critique of Quaternary overkill
and why it is largely irrelevant to the extinction debate. American Antiquity 77,
Venables, W.N., Ripley, B.D., 2002. Modern Applied Statistics with S. Springer, New
Walker, M., 2005. Quaternary Dating Methods. John Wiley, Sons, New Jersey.
Wroe, S., Field, J.H., Archer, M., Grayson, D.K., Price, G.J., Louys, J., Faith, J.T.,
Webb, G.E., Davidson, I., Mooney, S.D., 2013. Climate change debate over the
extinction of megafauna in Sahul (Pleistocene Australia eNew Guinea). Pro-
ceedings of the National Academy of Sciences USA 110, 8777e8781.
B.B.A. Araujo et al. / Quaternary International 431 (2017) 216e222222
... Other mechanisms could also be involved, e.g., greater disease limitation of human populations in long-occupied areas (Koch and Barnosky, 2006). Despite relatively strong evidence against a scenario in which climate change alone can explain late-Quaternary megafauna extinctions (Sandom et al., 2014;Bartlett et al., 2016;Araujo et al., 2017), the debate on the importance of humans is not settled (Hocknull et al., 2020;Lopes et al., 2020;Stewart et al., 2021;Wang et al., 2021). ...
... In this study, the latest, best-available data on paleoclimate, prehistoric and extant megafauna, and human biogeography is used to revisit the relative importance of climatic and anthropic factors in explaining the late-Quaternary megafauna extinctions. While there have been several global analyses of megafauna extinction patterns (Sandom et al., 2014;Bartlett et al., 2016;Araujo et al., 2017;Nogués-Bravo et al., 2010;Prescott et al., 2012), there are questions that can be asked about the nature of these extinctions that were not previously possible. Advances in climatic reconstruction can be used to determine local change in many factors between narrower periods. ...
... The existence of regions where climate change was comparatively moderate and where there was, nonetheless, very high extinction severity such as in South America shows that human activity is the necessary factor. While several analyses have shown a relationship between climate change and megafauna extinctions (Hocknull et al., 2020;Lopes et al., 2020;Stewart et al., 2021;Wang et al., 2021), these analyses are nearly always limited to a regional perspective, which constrains their ability to differentiate local extirpations from extinctions (Araujo et al., 2017). Regional studies are also less powerful when distinguishing human colonization patterns and climate change due to an increased risk of confounding the two events, as evidenced by the substantial overlap between areas of high climatic turnover and later human arrival found in this study. ...
The Earth has lost approximately half of its large mammal species (≥45 kg, one-third of species ≥9 kg) over the past 120,000 years, resulting in depauperate megafauna communities worldwide. Despite substantial interest and debate for over a century, the reasons for these exceptionally high extinction rates and major transformation of the biosphere remain contested. The predominant explanations are climate change, hunting by modern humans (Homo sapiens), or a combination of both. To evaluate the evidence for each hypothesis, statistical models were constructed to test the predictive power of prehistoric human and hominin presence and migration on megafauna extinction severity and on extinction bias toward larger species. Models with anthropic predictors were compared to models that considered late-Quaternary (120–0 kya) climate change and it was found that models including human factors outperformed all purely climatic models. These results thus support an overriding impact of Homo sapiens on megafauna extinctions. Given the disproportionate impact of large-bodied animals on vegetation structure, plant dispersal, nutrient cycling and co-dependent biota, this simplification and downsizing of mammal faunas worldwide represents the first planetary-scale, human-driven transformation of the environment.
... Martin's hypothesis attracted controversy which continues to the present day (Monjeau et al. 2017). However, it appears likely that human agency, in the form of hunting and habitat disruption, along with other factors such as climate change, did play a role (Araujo et al. 2017). The extent of this role is unlikely to be determined with any accuracy, but the likelihood that human beings played a part in such extinctions is supported by substantial evidence from across the world showing the decimation of indigenous species with the arrival of humans on previously uninhabited islands (de Nascimento et al. 2020;Diamond 1989;Matthews et al. 2020). ...
... However, this frequently extensive knowledge, as we have seen, will be embedded in distinctive worldviews, hermeneutic frames that can quite easily lead to environmental consequences that are by no means intended, and which often remain unacknowledged. Archaeological and anthropological evidence clearly shows that small-scale, low-technology societies can sometimes have significant environmental impacts that are predominantly due to the unintended consequences of their socio-technical practices in everyday life (Araujo et al. 2017;Diamond 1986Diamond , 2005Feeney 2019;Krech 1999;Martin 1967). It is also the case, as can be seen in Krech's study of Native American values, that, depending on the particular socio-environmental context, a belief system that appears to be ecologically friendly may in fact produce unintended consequences that can be interpreted as ecologically damaging. ...
Full-text available
Anthropocentrism has been proposed as the underlying cause of modern society's environmental impact. Concomitantly, hunter-gatherers' orientation towards nature is connected with minimal environmental change or conservation, and seen as validating the idea that ‘what people do about their ecology depends upon what they think about themselves in relation to things around them’ (White 1967: 1205). Here it is argued that the notion that orientation towards nature is instrumental in environmental impact in any generalisable way has little empirical support and, most importantly, is under-theorised and conceptually flawed. Employing a strong structurationist approach, it is shown that the tendency to abstract particular values from their social and environmental context must be resisted and that a deeper conception of the ‘inner lives’ of agents is required. Such an approach is more expansive and engages with a range of other motives as well as the unintended environmental consequences of actions.
... From a DAP perspective, niche construction can inform our understanding of cascading regime shifts in past landscapes and animal assemblages. In contrast to ongoing scholarly discussions on the dramatic extinction of large megafauna at the end of the last Ice Age, in which proponents of a 'climate hypothesis' are pitted against defenders of the 'human impact hypothesis' (Sandom et al. 2014;Araujo et al. 2017; Louys/Roberts 2020), animal niche construction provides an alternative explanatory framework for understanding the demise of past ecosystems in terms of animal agency itself, or rather the lack of particular forms of animal agency and its irreversible ecological consequences (whether additionally mediated by climate change and human interference nor not). As soon as the now-vanished Pleistocene ecosystems in question are recognised as partially coconstructed by animals (Bocherens 2018;Doughty 2017;Doughty et al. 2013;Owen-Smith 1987; see above), the loss of these ecosystems may be conceived as a result of missing or fundamentally restructured animal-centred ecosystem functions and services provided by past keystone and/or foundational species, eventually leading to systemic destabilisation, collapse and reorganisation (Mahli et al. 2016). ...
Full-text available
The deep past harbours exceptionally rich and diverse communities of non-human animals, and iconic species such as mammoth and reindeer are in the focus of popular and academic narratives on early human evolution. Yet paradoxically, the large majority of research on this critical timeframe continues to reinforce human-centred understandings of deep history and tends to overlook or even dismiss the role of animals as active agents and potent history-makers. This paper identifies three influential intellectual orientations which have contributed to this marginalisation of past animal agencies and legacies: anthropocentrism, environmental determinism and radical relationism. It then motivates and frames the project of ‘Deep Animal Prehistory’ (DAP) in an attempt to overcome some of the limitations tied to these orientations and to make space for the self-sufficient analysis of animals’ varied yet significant contributions to the remote past. This proposal offers a suite of new arguments for the importance and necessity of studying animal agency in the deep past, illustrating some of the advantages of adopting, developing and pursing a zoocentric research perspective. Key ideas and insights from human-animal studies and animal history are integrated with theories, taxonomies and perspectives from ecology, evolution, animal ethology and comparative behaviour studies providing a preliminary inventory of valuable concepts to trace, discuss and compare how non-human animals have influenced and shaped shared planetary pasts. In conclusion, this paper situates DAP within a broader, life-oriented approach to historical processes. It primarily formulates a critique on persistent anthropocentric tropes and categorisations in current palaeoarchaeological research, and catalogues emerging opportunities of empirical investigation and theory-building with the promise to counterbalance human-centred readings of the past, re-instating other animals to the heart of deep-historical accounts, narratives and debates.
... This is coincident with the Epipaleolithic era, where human subsistence dispersed from an origin in the African continent to cover all the globe's continents (except for Antarctica). While climatic changes may have been a component of the Late Pleistocene mass extinction of megafauna, high-resolution modelling of the timing of human arrival to world regions suggests that the anthropogenic impact through the hunting and killing of big game by Paleolithic Homo sapiens was the major cause of this mass extinction [37]. As the herds of big game disappeared, the late Epipaleolithic was characterized by an increase in the number of wild plant and animal species exploited by human hunter-gatherers, which eventually led to a few of those species being domesticated [38]. ...
Full-text available
De novo domestication is a novel trend in plant genetics, where traits of wild or semi-wild species are changed by the use of modern precision breeding techniques so that they conform to modern cultivation. Out of more than 300,000 wild plant species, only a few were fully domesticated by humans in prehistory. Moreover, out of these few domesticated species, less than 10 species dominate world agricultural production by more than 80% today. Much of this limited diversity of crop exploitation by modern humans was defined early in prehistory at the emergence of sedentary agro-pastoral cultures that limited the number of crops evolving a favorable domestication syndrome. However, modern plant genetics have revealed the roadmaps of genetic changes that led to these domestication traits. Based on such observations, plant scientists are now taking steps towards using modern breeding technologies to explore the potential of de novo domestication of plant species that were neglected in the past. We suggest here that in this process of de novo domestication, the study of Late Paleolithic/Late Archaic and Early Neolithic/Early Formative exploration of wild plants and identification of neglected species can help identify the barriers towards domestication. Modern breeding technologies may then assist us to break these barriers in order to perform de novo domestication to increase the crop species diversity of modern agriculture.
... While some argue that human overhunting caused the megafauna extinctions (Alroy, 2001;Haynes, 2018;Martin, 1973;Mosimann & Martin, 1975;Surovell et al., 2016;Surovell & Waguespack, 2008), others contend that the effect of humans on these extinctions is unclear. Instead, they propose that a combination of climatic changes and human interference caused the demise of megafauna such as proboscideans (mammoth and mastodon) (Agam & Barkai, 2018;Araujo et al., 2017;Barnosky, 2008;Barnosky et al., 2004;Grayson & Meltzer 2003;Koch & Barnosky, 2006;Meltzer, 2015). These inferential differences are rooted in an empirical problem, in that, the evidence for intensive human predation, butchery, or consumption of megafauna is exiguous and is often ambiguous (Eren et al., 2021;Grayson, 1984;Grayson & Meltzer, 2003;Meltzer, 2015), leading some archaeologists to conclude that the degree to which humans included hunted megafauna in their diet remains uncertain and, with respect to certain species, was possibly minimal (e.g., Eren et al., 2021). ...
Full-text available
Toward the end of the Pleistocene, the world experienced a mass extinction of megafauna. In North America these included its proboscideans—the mammoths and mastodons. Researchers in conservation biology, paleontology, and archaeology have debated the role played by human predation in these extinctions. They point to traces of human butchery, such as cut marks and other bone surface modifications (BSM), as evidence of human-animal interactions—including predation and scavenging, between early Americans and proboscideans. However, others have challenged the validity of the butchery evidence observed on several proboscidean assemblages, largely due to questions of qualitative determination of the agent responsible for creating BSM. This study employs a statistical technique that relies on three-dimensional (3D) imaging data and 3D geometric morphometrics to determine the origin of the BSM observed on the skeletal remains of the Bowser Road mastodon (BR mastodon), excavated in Middletown, New York. These techniques have been shown to have high accuracy in identifying and distinguishing among different types of BSM. To better characterize the BSM on the BR mastodon, we compared them quantitatively to experimental BSM resulting from a stone tool chopping experiment using “Arnold,” the force-calibrated chopper. This study suggests that BSM on the BR mastodon are not consistent with the BSM generated by the experimental chopper. Future controlled experiments will compare other types of BSM to those on BR. This research contributes to continued efforts to decrease the uncertainty surrounding human-megafauna associations at the level of the archaeological site and faunal assemblage—specifically that of the BR mastodon assemblage. Consequently, we also contribute to the dialogue surrounding the character of the human-animal interactions between early Americans and Late Pleistocene megafauna, and the role of human foraging behavior in the latter’s extinction.
... Large mammals perform a variety of ecological functions, including facilitation of seed dispersal over long distances 89,90 , maintenance of vegetation structure at the landscape-scale 91 , moderation of small mammal populations through competition and predation, and, perhaps most importantly, lateral transfer of nutrients 92 . The causes for the global megafaunal extinctions are still debated and there is conflicting evidence regarding the direct or indirect role played by humans 42,44,93,94 . Regardless of causal mechanisms, removal of ecosystem engineering megafauna and the resulting dominance of smaller-bodied mammals with different functional roles 42,87 had continental-scale ecological consequences for North American terrestrial ecosystems [95][96][97] , including geographic range expansions and shifts among surviving species 53,88 . ...
Full-text available
Biotic homogenization—increasing similarity of species composition among ecological communities—has been linked to anthropogenic processes operating over the last century. Fossil evidence, however, suggests that humans have had impacts on ecosystems for millennia. We quantify biotic homogenization of North American mammalian assemblages during the late Pleistocene through Holocene (~30,000 ybp to recent), a timespan encompassing increased evidence of humans on the landscape (~20,000–14,000 ybp). From ~10,000 ybp to recent, assemblages became significantly more homogenous (>100% increase in Jaccard similarity), a pattern that cannot be explained by changes in fossil record sampling. Homogenization was most pronounced among mammals larger than 1 kg and occurred in two phases. The first followed the megafaunal extinction at ~10,000 ybp. The second, more rapid phase began during human population growth and early agricultural intensification (~2,000–1,000 ybp). We show that North American ecosystems were homogenizing for millennia, extending human impacts back ~10,000 years. Biotic homogenization, which is increased similarity in the composition of species among communities, is rising due to human activities. Using North American mammal fossil records from the past 30,000 years, this study shows that this phenomenon is ancient, beginning between 12,000 and 10,000 years ago with the extinction of the mammal megafauna.
... This is in line with the hypothesis that a substantial part of Europe's current biodiversity is a result of co-evolution in low tree cover landscapes (Vera 2000). Open landscapes in Europe have existed for a long time thanks to native megafauna that was driven to extinction by human overhunting approximately 30,000 years ago (Araújo et al. 2017). Cultural landscapes kept open by human management form a kind of surrogate for these lost ecosystems (Sandom et al. 2014). ...
Full-text available
Aim of the report - This report aims to explore the importance of biodiversity in the context of European forests and to make suggestions on how this biodiversity can be effectively maintained and enhanced through protection, management and restoration. The term Europe in this document means European Union, except where mentioned otherwise. The report is meant for all kinds of decision-makers at the EU, national and local levels who are confronted with policy and management decisions related to biodiversity conservation and sustainable forest management. Although the primary focus is on the EU, most of the insights and recommendations made should be transferrable, with varying degrees of customisation where necessary, to non-EU countries as well. This report does not and cannot provide black and white guidelines on how to support forest biodiversity, rather it is designed to be a reference source for information and inspiration on the basics of forest biodiversity and forest biodiversity management. As such, it is a useful tool that highlights what is possible for evidence-based decision-making on this complex and dynamic matter. The report is purposely written and presented in a manner to stimulate dialogue on maintaining and restoring forest biodiversity while illuminating ways to bridge gaps between divergent viewpoints on the available options to avoid the loss of the irreplaceable and invaluable natural and cultural heritage inherent to European forest biodiversity.
The first of the Holocene’s three ages. The concept of the “ح” (“haa”) curve. The 3500 years spanning the transition from the LGM to the 8.2 k Event. The four pivotal changes occurring during the Greenlandian: (1) reduction in ice cover and an accompanying change in sea level, (2) significant changes to North Atlantic geography, (3) widespread extinctions, and (4) widespread cultural transformations.KeywordsLGMMegafauna extinctionMesolithicNeolithicDoggerland8.2 k event
Full-text available
El estudio de la distribución de especies es cada vez más necesario para entender las extinciones de megamamíferos ocurridas durante el Pleistoceno tardío y el Holoceno temprano. Procedimientos de análisis espacial, como el modelado cartográfico y las técnicas de evaluación multicriterio, permiten encontrar correspondencias espaciales entre variables geográficas, ambientales, faunísticas y humanas, para indagar en las causas de esas pérdidas. Desde una aproximación conceptual, el presente trabajo analiza características del abordaje interdisciplinario entre la Geografía y la Paleontología, el papel de los modelos espaciales insertos en el realismo científico, los procesos racionalistas de causalidad y las posibilidades de las técnicas cuantitativas en el análisis espacial sistémico tomando el caso del perezoso terrestre Scelidotherium leptocephalum (Mylodontidae, Xenarthra). Culmina con una propuesta de modelado cartográfico como construcción lógica de aplicación en la que la dimensión espacial toma un lugar central de indagación.
Discovering World Prehistory introduces the general field of archaeology and highlights for students the difference between obtaining data (basic archaeology) and interpreting those data into a prehistory, a coherent model of the past.
Full-text available
Examines 14C data in an attempt to resolve whether extinctions were synchronous or gradual. Results are inconclusive and concludes that current knowledge does not support either the climatic or the overkill hypothesis. Also evidence from 14C needs to be coupled with evidence relating to population dynamics, change and collapse, and the whole embedded in a viable and testable theory. -T.M.Kennard
Full-text available
Numerous anthropological and ecological hypotheses have been proposed to explain the extinction of many large-bodied mammals at the terminal Pleistocene. We find that body size distributions of all mammals in North America, South America, Africa and Australia before and after the late Pleistocene show a similar large-size selectivity of extinctions across con- tinents, despite differences in timing. All extinctions coincide with the colonization of the continent by aboriginal man, but only two coincide with periods of climate change. Further, historical (within the last 300 years) extinctions in Australia demonstrate a higher susceptibility of small and medium-sized mammals. On all four continents, large-bodied Recent mammals are threatened by human hunting practices, whereas small-bodied species are not. We conclude that the late Pleistocene extinctions were caused primarily by anthropogenic factors such as human hunting, whereas historical extinctions were due mostly to habitat alteration and exotic species introductions.
Full-text available
The overkill hypothesis has been criticized using a simple observation— with the exception of New Zealand, there is little evidence for human hunting of extinct Quaternary faunas. We explore the legitimacy of this argument, or what we call the “Associational Critique,” the idea that the paucity of evidence for the subsistence exploitation of extinct taxa weakens or falsifies overkill. Using quantitative and probabilistic models, based on the temporal depth of extinction events, human demography, and taphonomic bias, we ask how many associations with extinct fauna should have been found by this point in time in Australia, North America, and New Zealand. We conclude that such evidence should be rare in Australia, of intermediate abundance in North America, and common in New Zealand, a conclusion very much in accord with the current state of the archaeological record. We reach a similar conclusion using an analysis of the relative frequency of radiocarbon dates from each region dating to the time of coexistence of humans and extinct fauna. We argue that a scarcity of evidence for the exploitation of extinct fauna is not only consistent with overkill but also nearly every other extinction hypothesis that has been proposed, thus rendering the Associational Critique irrelevant.
Full-text available
The late Quaternary megafauna extinction was a severe global-scale event. Two factors, climate change and modern humans, have received broad support as the primary drivers, but their absolute and relative importance remains controversial. To date, focus has been on the extinction chronology of individual or small groups of species, specific geographical regions or macroscale studies at very coarse geographical and taxonomic resolution, limiting the possibility of adequately testing the proposed hypotheses. We present, to our knowledge, the first global analysis of this extinction based on comprehensive country-level data on the geographical distribution of all large mammal species (more than or equal to 10 kg) that have gone globally or continentally extinct between the beginning of the Last Interglacial at 132 000 years BP and the late Holocene 1000 years BP, testing the relative roles played by glacial-interglacial climate change and humans. We show that the severity of extinction is strongly tied to hominin palaeobiogeography, with at most a weak, Eurasia-specific link to climate change. This first species-level macroscale analysis at relatively high geographical resolution provides strong support for modern humans as the primary driver of the worldwide megafauna losses during the late Quaternary.
Full-text available
Cited By (since 1996):32, Export Date: 26 November 2013, Source: Scopus
Scrutinizes historic extinctions in a detailed attempt to fathom their meaning in the context of Late Pleistocene losses. Historic disappearances of modern birds and mammals can be laid to a variety of effects, some climatic, some cultural. Also considers 'the extinctions which did not occur'. -after Editor
Lima-Ribeiro and Diniz-Filho (2013) present a new compilation and analysis of the chronologies of human arrival and megafaunal extinction throughout the Americas. They find that in many places megafauna were apparently extinct before humans arrived; in many others, megafauna coexisted with humans for thousands of years before going extinct. They conclude that human impact made at most a minor and geographically restricted contribution to megafaunal extinction. We argue that Lima-Ribeiro and Diniz-Filho's (2013) conclusions are unreliable because they have not adequately accounted for uncertainties and biases that affect the estimation of extinction dates from fossil data and human-arrival dates from archeological data. We re-analyze their data taking these problems into account, and reach the opposite conclusion to theirs: extinction consistently followed human arrival with a delay of around one or two thousand years, in agreement with the overkill model of megafaunal extinction.