When mammoths roamed (rarely)

By Razib Khan | December 22, 2009 6:02 pm

Brian Switek, The extended twilight of the mammoths:

So, if the team’s analysis is correct, both mammoths and horses lived in the interior of Alaska between about 11,000 and 7,000 years ago. This is significantly more recent than the youngest fossil remains of horses and mammoths, dated between 15,000 and 13,000 years ago. There are at least two factors that might contribute to this disparity. The first is that fossils from this more recent time were preserved but have not yet been found. More likely, though, is that the populations of both mammoths and horses had dwindled to the point where fossil preservation was becoming increasingly unlikely. There were so few of them that the death of an individual in circumstances amenable to preservation was becoming rarer and rarer.
Either way, this discovery has important implications for the extinction of horses and mammoths in North America. Based upon the fossil data alone it had been hypothesized that both disappeared around the time that humans became established in North America.* Some have taken this association to suggest that humans engaged in a blitzkrieg in which naive New World megamammals were quickly dispatched by the human hunters. If the new evidence is correct, though, humans did not wipe out horses and mammoths overnight. Instead humans lived alongside dwindling populations in Alaska for thousands of years. Likewise, these new findings also contradict the favored hypothesis of one of the study’s authors, Ross MacPhee, who previously proposed that some kind of “hyperdisease” carried by humans (or animals that traveled with humans) quickly wiped out these animals. The pattern of extinction was obviously more protracted.

This seems about right. Excuse the analogy, but it sometimes seems that models of human-caused extinction of mega-fauna portray ancient hunter-gatherers as Einsatzgruppen, and the mega-fauna as Jews and Communists. Though genocides of human populations in the concerted manner of the Germans against the Jews, Gypsies and other groups during World War II have occurred periodically, more often what we see is a slow wearing down and attrition of marginal groups at the expense of dominant ones.
It seems a plausible model that when mega-fauna were plentiful hunters would focus on them, but once the mega-fauna became rare naturally the return on investment would decrease and it would become rational to shift to other prey organisms. This implies that many mega-fauna likely persisted in isolated pockets as relict populations, and may have been killed off only far later, or perhaps even succumbed to a natural environmental calamity. In another era the last herds of wild horses would probably have gone extinct due to drought, or perhaps been hunted down by a random group of humans who had no idea that they were decreasing the biological diversity of the planet.

CATEGORIZED UNDER: Ecology
  • http://historyanarchy.blogspot.com History Punk

    Excuse the analogy, but it sometimes seems that models of human-caused extinction of mega-fauna portray ancient hunter-gatherers as Einsatzgruppen, and the mega-fauna as Jews and Communists.”
    I’m a fan of historically informed hyperbole, but wow this has got to take the cake.

  • http://scienceblogs.com/gnxp razib

    well, one of the theories of mega-faunal extinction is called the “blitzkrieg theory.”

  • http://entitledtoanopinion.wordpress.com TGGP

    On the opposite end of the scale, in the computer game Syberia (which I haven’t played) the conventional wisdom among anthropologists about a tribe of arctic hunter-gatherers is that for thousands of years after the extinction of mammoths they’ve been living off a diet consisting of the meat from mammoths that froze way back when. Who thinks that top-level predators are severely constrained by the population of prey? Not the intended audience of that game, apparently!

  • http://www.scienceblogs.com/casaubonsbook Sharon Astyk

    I recently heard a talk (about something completely unrelated – historical Native settlements on waterways) by an Algonquin historian who was deeply indignant about what he described as a “calumney” that attributes the extinction of the megafauna to his ancestors. He observed that his people had stories/histories that orally transmitted at least some of their history of interaction with the megafauna, and they indicated a more complex decline. I had no particular investment in any position on this, but find it interesting that the archaeological evidence may bear him out.
    Sharon

  • Don

    Razib: Sitzkrieg.
    Diamond 1986. Journal of Archaeological Science
    Volume 16, Issue 2, March 1989, Pages 167-175
    Quaternary megafaunal extinctions: Variations on a theme by paganini
    Jared M. Diamond
    Abstract
    Evidence from modern witnessed extinctions may help us separate contributions of human-related and climate-related factors to the much-debated late-Quaternary extinctions of megafauna. Some witnessed human-related extinctions are blitzkriegs of overhunting (á la Mosimann and Martin), but more are slow attritions or sitzkriegs involving mechanisms besides overhunting. Consideration of these mechanisms makes it unlikely that the first human colonists of Australia and New Guinea …

  • http://blog.ninapaley.com Nina Paley

    Today humans cause extinctions indirectly, through changing habitats faster than other species can adapt. It seems likely that’s what killed ancient megafauna too. Not direct hunting, but perhaps burning and other disruptive activities.

  • http://bluetenlese.wordpress.com M. Möhling
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About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com

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