Why are Pygmies short?

This recent article suggests that the pygmy phenotype has evolved a number of times in Africa.

A Batwa young man in Bwindi Impenetrable Forest National Park, Uganda (from the article).

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A Batwa woman in Bwindi Impenetrable Forest National Park, Uganda.

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Here is the Wikipedia article on Pygmies.

The article above suggests that the small body size of pygmies may be adaptive for a number of reasons, including heat dissipation, shortage of food in the rainforest and easing movement through the forest. Other possible explanations, including a short lifespan promoting early reproduction at the expense of body size, and a suggestion I published years ago, namely that small skeletal size is an adaptation to low levels of ultraviolet light and therefore vitamin D production for bone growth, are discussed at the Wikipedia article.

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13 responses to this post.

  1. Posted by Julian O'Dea on August 30, 2015 at 7:49 am

    https://westhunt.wordpress.com/2015/08/17/something-else/

    And here:

    http://www.unz.com/gnxp/the-genetic-architecture-natural-history-of-pigmentation/

    On light skin and vitamin D.

    https://en.wikipedia.org/wiki/Vitamin_D

    “Evidence indicates the synthesis of vitamin D from sun exposure is regulated by a negative feedback loop that prevents toxicity …”

    “Adequate amounts of vitamin D can be produced with moderate sun exposure to the face, arms and legs, averaging 5–30 minutes twice per week without sunscreen. (The darker the complexion, or the weaker the sunlight, the more minutes of exposure are needed, approximating 25% of the time for minimal sunburn. Vitamin D overdose is impossible from UV exposure; the skin reaches an equilibrium where the vitamin degrades as fast as it is created.)”

    http://www.post-gazette.com/news/science/2015/04/20/The-roots-of-color-in-our-skin-Our-hue-indicates-nothing-more-than-a-need-for-vitamin-D/stories/201504190050 (Nina Jablonski)

    Reply

  2. […] In my opinion, Cochran has done it again with his latest arguments that the gene for white skin in northern Europeans probably has to do with something other than increasing vitamin D production in low ultraviolet conditions, the traditional explanation (see the reference to Nina Jablonski’s work in the comments on my post here). […]

    Reply

  3. Posted by Julian O'Dea on September 29, 2016 at 1:51 pm

    Ancient exploitation of rainforests:

    http://blog.everythingdinosaur.co.uk/blog/_archives/2015/03/15/those-highly-adaptable-humans.html

    (It would be interesting to check if the skeletal remains showed evidence of dwarfing like modern Pygmies.)

    Reply

  4. Posted by Julian O'Dea on October 16, 2016 at 5:11 am

    http://www.wettropics.gov.au/rainforest_explorer/Resources/Documents/8to9/BamaCountry.pdf

    Bama peoples including Yalanji (https://www.thalabeach.com.au/kuku-yalanji/)

    “The Bama themselves tended to be of shorter stature than other Aboriginal Australians
    although in other psychological respects they were no different. This may have been an
    advantage to gaining access to the rainforest canopy in order to hunt animals. The short
    statured Bama “with his trained eye… will immediately discover whether a tree kangaroo, a
    possum or a glider has been up or down the tree. Their sharp claws always leave a mark of
    some air gets caught in the crack of the bark.” The impressiveness of these feats can be
    gauged by Meston’s observation that “it would severely tax the readers’ credulity to describe
    how these natives take a vine and run up the tallest trees, walk onto others across the
    branches and descend sometimes a considerable distance from the starting point.””

    Reply

  5. Posted by Julian O'Dea on October 16, 2016 at 9:30 am

    http://www.theaustralian.com.au/national-affairs/indigenous/sidelined-to-centre-stage-for-daintree-guardians/news-story/310a2775d85af331a89aa51f9ac37e8b

    Refers to Yalanji (with picture of Yalanji woman).

    If this copy is unavailable, try searching Google on:

    “daintree guardians the australian”

    Reply

  6. Posted by Julian O'Dea on November 19, 2016 at 5:44 am

    http://researchonline.jcu.edu.au/27492/

    “Horsfall, N. (1987) Living in rainforest: the prehistoric occupation of North Queensland’s humid tropics. PhD thesis, James Cook University.”

    Jiyer Cave, 5100 BP.

    http://researchonline.jcu.edu.au/27492/1/27492-horsfall-1987-thesis-volume-1.pdf
    http://researchonline.jcu.edu.au/27492/2/27492-horsfall-1987-thesis-volume-2.pdf

    Reply

  7. Posted by Julian O'Dea on March 14, 2017 at 4:23 am

    My observations on UV light in the rainforest as they relate to captive Sumatran rhinos:

    http://www.rhinoresourcecenter.com/index.php?s=1&act=refs&CODE=note_detail&id=1165254908&highlite=

    Reply

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