Environmental Engineering Reference
In-Depth Information
Box 7.2
Late Pleistocene Hunting: Megafauna and Meat Consumption
A late Pleistocene population of at least two million people would translate (assuming
an average body mass of 40-45 kg per capita) into roughly 100,000 t of fresh-weight
anthropomass. As already noted (see box 7.1), even if we assume very high food energy
needs for these (sometimes highly mobile) foragers, the average per capita rate (includ-
ing all children and adults) could not have been higher than about 10 MJ/day. To arrive
at a (perhaps unrealistically) high limit on the overall kill would be to assume that, as
argued by Mosimann and Martin (1975), the late Pleistocene foragers ate mostly meat,
that about 80% of their food needs came from megafaunal species (and the rest mostly
from smaller herbivores), and that the live weight of killed animals was 2.5 times the
weight of their edible tissues, whose average energy density was as high as 10 MJ/kg.
These assumptions would require an annual kill of nearly 2 Mt (fresh weight) of
megafaunal zoomass, approximately 20 times higher than the global anthropomass at
that time. If all of the killed animals were mammoths (an unrealistic assumption made
in order to get the minimum number of slaughtered animals), then the annual kill—
assuming a mixture of
Mammut americanum
,
Mammuthus primigenius,
and
M. merid-
ionalis
(weighing 4-9 t) and a larger
Mammuthus imperator
weighing more than 10 t
(Christiansen 2004)—would have amounted to no less than 250,000 animals and as
many as 400,000 animals. Assuming, more realistically, that the largest animals domi-
nated the mixture of hunted megafaunal species, whose average weighted body mass
was on the order of 1 t/head, then the total annual kill could easily have been on the
order of two million large mammals.
The annual energy requirements of those killed animals could be approximated
fairly well either by using standard metabolic equations (Dong et al. 2006) or by cal-
culating their free-ranging metabolic rates from the best available allometric equations
(Nagy 2005) and then assuming 11 MJ/kg of dry matter as the average energy density
of the phytomass grazed by large herbivores. For a grazer weighing 1 t, the need would
between 100 and 125 MJ/day, or an equivalent of about 9-11 kg of dry-matter phy-
tomass. Two million large herbivores would thus have consumed annually 7-8 Mt of
dry phytomass, a mass two orders of magnitude larger than that of all wood used for
cooking but still less than 0.001% of all terrestrial phytomass in place during the late
Pleistocene period. The total phytomass consumption would be smaller for the same
overall zoomass if the average mass per head were larger (that is, if most killed species
were mammoths rather than large bison or aurochs) because specii c metabolism
declines with body mass.
