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paleoanthropology, genetics and evolution

fauna

  • Reindeer associations

    Sat, 2012-12-22 22:50 -- John Hawks

    Alice Roberts ponders the prehistory of people and reindeer: "Rudolph and our early ancestors – a love story".

    The end of the ice age saw a massive global extinction: many large mammals fell prey to changing climate and the effect of some rather formidable hunters sharing their landscape. There was a decline in the genetic diversity of reindeer after the peak of the last ice age 20,000 years ago – probably due to a warming climate as well as those palaeolithic hunters – but reindeer survived, and thankfully they don't look likely to become extinct any time soon.

    Tags: 
    fauna
    glaciations

  • Reindeer hides and Neandertals

    Sun, 2012-06-24 10:08 -- John Hawks

    In reference to the post below about Quina Mousterian and reindeer specialization ("Paleoclimate and shifting Neandertal strategies"), let me add this great quote from Mark White. He addresses himself to the question of what kinds of strategies Neandertals employed against the cold of the MIS 4 winter in Britain and France.

    Aiello and Wheeler hypothesize a very conservative 1 clo of insulation. The pelts of exploited Pleistocene mammals would have greatly exceeded this level (cf. Stenton 1991: 11), meaning that a clothed Neanderthal could have remained comfortable at temperatures far below those outlined above. Reindeer hides are particularly valued by modern arctic peoples because they are lightweight and their fur has excellent insulatory properties (clo value = 7: ibid.). The best time to procure reindeer hides is in the late summer, prior to the development of the heavy winter pelage and after the skin had repaired the damage caused by any summer parasites (ibid.: 6), which adds another interpretative dimension to the autumn mass killing of reindeer at Salzgitter-Liebenstedt (Gaudzinski and Roebroeks 2000); especially if Bocherens et al. (2005) are correct in their assertion that northern Neanderthals ate a lot of mammoth and rhino, but little reindeer (the reverse being true for hyenas). One wonders whether some species were targeted as much for their hides and sinews as for their meat value (see Burch (1998) for caribou), and whether the classic ‘scavenging’ pattern of heads and lower limbs found in Middle Palaeolithic sites is in fact a signature testifying to the preferential transport of hides away from the kill sites (cf. Chase 1986; Mellars 1996). Indeed, such patterns find obvious parallels in medieval tanneries (Serjeantson 1989; Gidney 2000). The broad association of scraper-rich Quina assemblages with colder environments and reindeer bones is highly suggestive in this regard (cf. Mellars 1996: 329; Dibble and Rolland 1992).

    The quote is from another paper with an awesome title, "Things to do in Doggerland when you're dead" [1]. He adds that in Britain a a major limitation on Neandertals may have been the lack of wood -- not only for fire, but also for construction of long implements such as spears. The evidence for woodworking at some sites suggests they may have been located near stands of trees that persisted during the spread of periglacial steppes. All in all, it's a very interesting paper.

    References

    1. White MJ. Things to do in Doggerland when you're dead: surviving OIS3 at the northwestern-most fringe of Middle Palaeolithic Europe. World Archaeology. 2006;38(4):547 - 575.
    Tags: 
    hunting
    Neandertals
    Britain
    Europe
    Middle Paleolithic
    fauna

  • What the cat didn't drag away

    Thu, 2012-05-03 17:50 -- John Hawks

    Digging through some literature this afternoon, I ran into a 2007 paper by Denise Su and Terry Harrison [1], who mounted several explanations for why Laetoli, Tanzania, has a relatively low abundance of Au. afarensis fossils compared to other sites. They suggest a size-sorting bias due to predation, which would disproportionately have affected postcranial bones:

    The evidence supports the inference that, with increasing body size of the prey species, there is a greater chance that skeletal elements will survive complete destruction by carnivore scavenging. This results in a higher representation of postcranial elements relative to craniodental remains as body size increases. However, the converse means that species in the lower weight categories are increasingly susceptible to being entirely destroyed by carnivores. Hominins, which occur in the lowest end of the range for WC II, would be among those large mammals expected to be most heavily affected by the greatest number of species with the ability to completely remove skeletal elements from the skeletal assemblage at Laetoli. If this model is correct, then it is not unexpected that so few postcranial bones of hominins have been recovered. In fact, it is precisely what would be predicted at an open-air site with subaerial deposition in which the skeletal assemblage was readily accessible to carnivore scavengers.

    They also point to the variation in the abundance of living chimpanzees and other primates in different ecologies.

    Extant chimpanzees occur at a wide range of population densities across equatorial Africa according to habitat. Densities range from 0.08–0.09/km2 in open woodland (Ugalla, Tanzania; Mount Assirik, Senegal) to 3.1–4.7/km2 in closed woodland and forest (Gombe, Tanzania) (Plumptre and Cox, 2006), an almost sixty-fold difference between marginal and optimal habitats. This observation gives us a better appreciation of how different types of habitat can influence the biomass of African hominoids. It can be assumed that similar levels of population-density variation would have characterized A. afarensis across its geographic range. Given this fact, if A. afarensis at Hadar is indeed more common than at Laetoli, then it would suggest that Hadar had habitats that were more optimal for sustaining higher population densities of A. afarensis compared to Laetoli. The magnitude of the difference between the specimen counts between Hadar and Laetoli are equivalent to the difference in population density between modern-day chimpanzees living in closed and open woodland habitats, respectively.

    Based on the fauna -- which interestingly include some rat genera now absent in East Africa but present in India and Southeast Asia -- along with other indicators, they infer that Hadar had more woody cover than Laetoli during the period represented by the hominins.

    References

    1. Su D, Harrison T. Ecological implications of the relative rarity of fossil hominins at Laetoli. Journal of Human Evolution. 2008;55(4):672 - 681.
    Tags: 
    paleoenvironment
    Laetoli
    Hadar
    fauna
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Neandertals

For years, I've worked on their bones. Now I'm working on their genes. Read more about the science studying these ancient people.

Denisova

From a finger bone of an ancient human came the record of a completely unexpected population. My lab is working on the science of the Denisova genome.

Acceleration

The advent of agriculture caused natural selection to speed up greatly in humans. We're uncovering some of the ways that populations have rapidly changed during the last 10,000 years.

Malapa

Just outside Johannesburg, the Malapa site is producing some of the most exciting finds in human evolution. This site is the headquarters of the Malapa Soft Tissue Project.