9 comments on “Bipedal – The Savanna Theory

  1. Just a comment on the deer standing on their hind legs. It has been so dry and I see many deer reaching really high branches to feed on the green leaves. I would not have thought they could do it so easily and with good balance too.

    A neighbor trimmed a lot of his trees recently. Many branches full of leaves. In less than a day the deer had stripped every leaf off. He just had to cut up the branches and dispose of them. It was one time we were glad for the deer feeding on them. They eat almost everything in sight. 🙁

  2. It’s the same here. They really seem to like the ornamental cedars, which all look like mushrooms now. They like the rose blossoms in our yard, too. Unfortunately we’re getting more deer attacking people, with some serious injuries.

    rjb

  3. I have seen more bucks out in the open this year. Usually they are alone. But recently seeing maybe 4-5 in a group. I try to head in the other direction.

  4. Around here it seems to be the females attacking people, usually when they have young, and very often when there’s a dog involved. The dog will go barking at the deer, then get scared and run back to the human, followed by the deer.

    rjb

  5. The conventional view – that human ancestors became bipedal by moving from the forests to the plains (schematically: ape=>human = forest=>plain = 4-legged=>bipedal) – is biologically & physiologically impossible, e.g. primates that move from forest to savannah become not less, but more quadrupedal (“the baboon paradox”); sweating requires salt & water (both scarce in arid grasslands); etc. An account of human evolution which mentions possible arboreal & terrestrial but not shallow-aquatic milieus is incomplete.
    Comparative, paleo-environmental & other data show:
    (1) Plio-Pleistocene australopithecines were typically wetland species (K.Reed 1997). This helps explain the remarkable combination of bipedality (e.g. for wading) & curved hand-bones (for climbing aems overhead). Human fetuses never have hand-like feet, but prenatal African apes have more humanlike feet (with longer & adducted big toes) which later become more hand-like (C.Coon 1954). This suggests Pan & Gorilla had more bipedal ancestors (e.g. for parttime wading for papyrus, frogbit, waterlilies etc.), google e.g. bonobo wading, or gorilla bai.
    (2) Our Pleistocene ancestors (archaic Homo) did not disperse intercontinentally walking or running over the open grasslands, but followed African & Eurasian coasts & rivers (coastal dispersal model, S.Munro 2010), walking & wading bipedally & parttime diving for waterside, littoral & shallow-aquatic foods (which are richest in brain-specific nutrients such as DHA, e.g. S.Cunnane 2005), even colonizing islands overseas: Flores, Crete, Cyprus etc. Homo’s diet included animal (e.g. shellfish to be opened with hard tools, waterside carcasses of herbivores & marine mammals, salmon & other fish) as well as plant foods (e.g. traces of waterlily roots in neanderthal dental calculus & of cattails on their tools).
    Homo’s brain enlargement (DHA) & parttime shallow diving (which requires breathing control) were preadaptive to human spoken language.

  6. Savannah apes became bipedal mainly to allow them to carry weapons such as clubs fashioned from tree roots – or stones to throw at animals. I don’t think bipedalism would have ever allowed them to outpace an antelope. I am inclined to think that as a small group, and there is a tribe in Sudan that still does this today, they would shoo off a lion from its fresh kill. This is done by throwing stones at the lion or charging at it with their clubs and screaming loudly. Bipedalism is also needed for carrying the kill – or parts of it – back to the community.

    Bipedalism also allows a vision above the elephant grass which can be relatively high in some areas and is also essential for wading in the East African lakes or the wet lands of the upper Nile region.

  7. Most likely, Miocene hominoids were already preadapted to bipedalism.

    Early hominoids frequently fossilized in swampy & coastal forests, where they probably already frequently waded bipedally.
    Bonobos & lowland gorillas still do this in search for waterlilies, sedges & other aquatic plants, google “bonobo wading” or “gorilla bai”.
    Hominoids wading bipedally could climb trees by grasping branches above the head.

    This wading-climbing locomotion could explain different hominoid traits, e.g.
    – larger body,
    – tail loss,
    – broad body: thorax, sternum, pelvis,
    – centrally-placed spine (vs. dorsally in monkeys & most mammals).

    We argued that this aquarboreal locomotion (aqua=water, arbor=tree) could have preadapted to human “full” bipedalism.
    Google “aquarboreal”.

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