Re: kudu runners


only a complete idiot believes that you evolve heavier bones to run over
savannas

Running does indeed result in higher bone density.

when you compare people like you sitting on a chair with athletes yes

not when you compare normal cursorials with erectus:

Pachyosteosclerosis in Homo erectus and archaic Homo suggests exploitation
of sessile aquatic foods
Stephen Munro & Marc Verhaegen 2009

The cranial and postcranial bones of Homo erectus and other archaic Homo
fossils were typically massive, displaying generalised hyperostosis or
pachyosteosclerosis: extremely thick bones (pachyostosis), compact bone
cortices (osteosclerosis), and narrow marrow canals (medullary stenosis).
No other primates, fossil or extant, including apes, australopithecines, and
Homo sapiens, display this remarkable feature, and even outside the primate
order, examples of animals with such heavy bones are rare.
Pachyosteosclerosis is often used to help identify H. erectus fossils, but
surprisingly few convincing hypotheses have been put forward to explain its
functional and adaptive significance.
We first show that unusually heavy skeletons were a typical, although not
exclusive nor indispensable, characteristic of Homo erectus and other
archaic Homo fossils of the early, middle and late Pleistocene (~1.8 Ma to
~10 ka) in areas of South and East Asia, Africa and Europe.
We then review the occurrence of massive bones in other tetrapods. This
suggests that they are more brittle than bones of a ?normal¹ histology, and
that heavy bones have an important hydrostatic function in species that
regularly dive or wade in shallow water, and are part of a set of
adaptations that allows more efficient foraging for sessile foods such as
aquatic vegetation or hard-shelled invertebrates.
Therefore we consider whether H. erectus and other archaic Homo populations
might have been exceptions to the rule, or whether part-time shoreline
collection of sessile aquatic foods in relatively shallow waters might have
been possible when they dispersed to other continents along the coasts and
from there inland along lakes or rivers. A review of the palaeo-ecological
data shows that most, if not all, H. erectus fossils and tools are
associated with water-dependent edible molluscs and large bodies of
permanent water.
We discuss the alternative explanations for pachyosteosclerosis from the
literature ­ including heavy exertion, endurance running, fighting with
large prey, or protection against intraspecific violence ­ as well as the
apparent exceptions to the rule, such as thin-boned H. erectus (KNM-OL
45500) and thick-boned H. sapiens (Kow Swamp) fossils.
Since fresh and salt water habitats have different densities, we hypothesise
that in H. erectus as well as in some H. sapiens populations, there might
have been a positive correlation between massive bones and dwelling along
sea or salt lake shores. Arguably there existed cyclic adaptations during
the Pleistocene, with alternatingly Homo populations generally becoming more
littoral and more relying on shellfish on the continental shelves during
glacials (when sea levels were up to 120 metres lower than today) and
shifting, seasonally or more permanently, towards more inland waterside
dwelling during interglacials.

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