Expert: John Shea - 8/12/2005

Question
Hello John,
I'm having a bit of a (mild!) argument with someone on a Yahoo! list archive where I've stated that Palaeolithic-age humans did violent exercise during the day on a continuous basis. The other person stated that this was all a myth, and that most hunters just went to where they knew the animals were, killed one of them on the spot as the herd passed by, and that was it. He seemed to imply that Stone-Age people just sat around all day, doing very little exercise.
My own view is that the Romantic view of humans running every day to hunt  wild animals is perhaps a myth(though I may be mistaken) - However, given that they were nomads, they must have done a hell of a lot of violent exercise during the day just in terms of migration, let alone for other reasons.

What's your take on this point?
Thanks in advance
Geoff Purcell
London UK

Answer
Hello Geoff,
(You caught me in a break between crunching numbers on an archaeology report, -I usually don't reply so quickly.)  Put simply, the bulk of the evidence is on your side.  Paleolithic (pre-agricultural) humans, both Homo sapiens and our predecessors, have degrees of skeletal robusticity that one only sees today among highly competitive amateur and professional athletes.  There are three lines of evidence to confirm this.
Cortical Bone Thickness -bone rebuilds itself by filling in microcracks caused during strain.  More strain = more cracks = thicker cortical bone.  Paleolithic cortical bone thicknesses are typically at the extreme range of modern human variation.  For references on this, see the work of Chris Ruff (Johns Hopkins Univ.) and Erik Trinkaus (Washington Univ).
Cranial Vault thickness - when you exercise, your body secretes hormones that stimulate bone repair (see above), this also causes bone to grow in areas that are not being actively strained, like one's skulls.  Paleolithic humans have cranial vault thicknessess several times those of recent humans.  References to this research -Look up Daniel E. Lieberman (he's at Harvard and his lab has a good website.)
Damage and Pathology -comparisons of breakage and damage patterns on the skeletons of paleolithic humans have their nearest analog among living humans who work as rodeo athletes (both riders and "clowns" -the latter don't fool around, they jump around to distract the bull so that a thrown rider can escape).  The only difference is that paleolithic humans do not appear to have survived major breaks to their lower limbs (they probably abandoned severely-injured individuals).  This study was done by Tomy Berger.  (I don't know where he is based now, but you can probably track him down with Google.)  If you need scientific references by any of the people whose names I have mentioned, use the "Scholar" option on Google and you'll find what you need.
The kind of low-effort hunting strategy your correspondent describes is probably a recent development, something that's a byproduct of firearms or other distance-killing projectile technologies.
Cheers,
John Shea