Ray Audette made an interesting comment in a previous digest, noting
that a man with 6 dogs and an atlatl would have been a formidable
predator capable of mass extinction of large pleistocene mammals. Much
has been written on man's role in the wide scale extinctions of large
mammals that occurred at the end of the pleistocene:
1. Stuart AJ. Mammalian extinctions in the late pleistocene of
northern eurasia and north america. Biol Rev 1991 66:453-62.
2. Martin PS. The discovery of America. The first Americans may have
swept the western hemisphere and decimated its fauna within 1000 years.
Science 1973 179:969-74.
3. Diamond J. The American blitzkrieg: a mammoth undertaking. Discover
1987 June:82-88.
4. Diamond J. The golden age that never was. Discover 1988 Dec:71-79.
5. Martin PS. 40,000 years of extinctions on the planet of doom.
Palaeogeography, Palaeoclimatology, Palaeoecology 1990 82:187-201.
6. Haynes CV. Elephant hunting in north America. Sci Am 1966
214:104-112.
7. Grayson DK. The chronology of Northa American late Pleistocene
extinctions. J Archaeol Sci 1989 16:153-65.
8. Mosimann JE, Martin PS. Simulating overkill by paleoindians. Am Sci
1975 63:304-313.
During this period , which presumably coincided with increasing
technological development and increasing human populations, South
America lost 46 out of 58 genera (80%) of mammals exceeding 44 kg;
Australia 15 out of 16 (94%); North America 33 out of 45 (73%). For
Europe and Africa the figures are considerably lower (7 out of 24 - 29%)
and (2 out of 44 - 5%) respectively. These mass extinctions affected
large terrestrial mammals exclusively, whereas invertebrates, small to
medium terrestrial vertebrates, plants and marine vertebrates continued
almost unscathed.
Martin and others believe that human overkill was largely responsible
for the extinction of these large mammals and that many of these huge
behemoths were wastefully killed and only certain portions of the
carcass were selectively consumed. Present day hunter gatherers
prefer fatty portions of the carcass (organs, brains, marrow, tongue,
fat depots, fatty cuts of meat) , and it is likely that our ancestors
did as well. Butcher marks on mammoths in a number of european sites
indicate cut marks which suggest that tongues were highly prized.
Ray Audette suggested that many of the mammals that became extinct
during this period were those which stored the most adipose tissue, and
hence were selectively preyed upon. Although, we have no way of
determining the body composition of extinct animals, it is likely that
high northern and southern latitude mammals probably had to store fat
similar to modern mammals living in seasonal climates to survive through
the winter. Given modern man's preference for fat, it is no less
likely that our ancestors did not seek out fat and fatty animals as
well. Further, because of selective utilization of animal tissues
(both pre-historically and in present day hunter-gatherers), the fat
content of the human diet could have easily exceeded estimates of 15-20%
of the total caloric intake which have been widely used as a model for
the paleolithic diet.
The other point worth noting here is that for most "paleolithic meals"
protein and fat would have almost always occurred together (since these
two elements always were present with the kill - except for small stores
of liver and muscle glycogen, animals are virtually devoid of
carbohydrate) , whereas carbohydrates from collected plant foods would
have more often been eaten separate from the protein/fat combination.
The health implications of these ancestral macronutrient combinations
are critical for modern man. Recent studies show that high fat, high
CHO meals tend to increase post-prandial lipemia compared to lower CHO
meals, and that elevated blood lipid levels in the post-prandial period
are a significant risk factor for CHD (Chen Y.D. et al. Effect of
variations in dietary fat and carbohydrate intake on postprandial
lipemia in patients with noninsulin dependent diabetes mellitus. J Clin
Endocrin Metabol 1993 76:347-51.). Taken together with Wolfe's data
(Wolfe BM. Potential role of raising dietary protein intake for
reducing risk of atherosclerosis. Can J Cardiol 1995 11:127G-131G)
showing isocaloric replacement of CHO with animal based protein results
in lowered total CHOL, LDL, VLDL, TG and increased HDL, these
experiments tend to confirm that our ancestral eating habits of
combining fat with high amounts of protein produces a less atherogenic
profile than combining high levels of carbohydrate with high levels of
fat. Preliminary data from our laboratory utilizing game meat
consumption confirms this general concept (Tillmans C, Cordain L, Harris
et al. Game meat is an effective dietary component in lowering serum
cholesterol. Proc Rocky Mtn Chapt ACSM; abstract, 1995).
Cordially,
Loren Cordain, Ph.D.
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