New carbon dates link climatic change with human colonization and Pleistocene extinctions


Drastic ecological restructuring, species redistribution and extinctions mark the Pleistocene–Holocene transition, but an insufficiency of numbers of well-dated large mammal fossils from this transition have impeded progress in understanding the various causative links1. Here I add many new radiocarbon dates to those already published on late Pleistocene fossils from Alaska and the Yukon Territory (AK–YT) and show previously unrecognized patterns. Species that survived the Pleistocene, for example, bison (Bison priscus, which evolved into Bison bison), wapiti (Cervus canadensis) and, to a smaller degree, moose (Alces alces), began to increase in numbers and continued to do so before and during human colonization and before the regional extinction of horse (Equus ferus) and mammoth (Mammuthus primigenius). These patterns allow us to reject, at least in AK–YT, some hypotheses of late Pleistocene extinction: ‘Blitzkrieg’ version of simultaneous human overkill2, ‘keystone’ removal3, and ‘palaeo-disease’4. Hypotheses of a subtler human impact and/or ecological replacement or displacement are more consistent with the data. The new patterns of dates indicate a radical ecological sorting during a uniquely forage-rich transitional period, affecting all large mammals, including humans.

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Figure 1: A plot of radiocarbon dates on AK–YT mammoth, horse, bison, wapiti and moose bones that fall within the 18–9 kyr  bp interval, shown alongside dated archaeological material (hearth charcoal mainly) from the same regions8.
Figure 2: A visual model linking large mammal date patterns (Fig. 1) to a changing ecological context.


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I thank curators R. Tedford, R. Gangfloff, R. Harington and R. Purdy for dating access to museum collections, and M. L. Guthrie, F. Dean and D. Murray for suggestions that improved the manuscript. I also thank the NSF and the Tucson AMS laboratory.

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Correspondence to R. Dale Guthrie.

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Supplementary information

Supplementary Notes 1

The first section of the Supplementary Information summarizes information about the radiocarbon dates used in this study, their collection, and possible taphonomic problems pertaining to their collection. This is a necessary background to understanding the dates which are listed in the second section of the Supplementary Information. (DOC 31 kb)

Supplementary Notes 2

The second section is a list of radiocarbon dates plus their specimen identification, location, provenance etc., for both the new dates referred to in this study and the data set of relevant older published dates. (XLS 106 kb)

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Dale Guthrie, R. New carbon dates link climatic change with human colonization and Pleistocene extinctions. Nature 441, 207–209 (2006).

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