The Discovery of Sex j 1313 13
with the result that the average temperature in central and southern Europe was about 18°F
(10°C) lower than modern levels. Nevertheless, these conditions, which are similar to those
of present- day southern Alaska or northern Scandinavia, supported a rich fauna of large
herbivores, such as reindeer, horses, and bison, which provided an ample food supply for
early modern humans. So, despite the often harsh conditions that prevailed in Western
Europe, the abundance of wild game in southern refugia ensured the survival of modern
humans and even provided them with a measure of prosperity and leisure.^3
Perhaps as a result of their material success, Western Europeans in the Upper Paleolithic
experienced an artistic explosion unlike anything that had gone before. Such an outpour-
ing of creative expression must have reflected a quantum leap in overall cultural complex-
ity, including new developments in art (painting, sculpture, music, dance, story- telling),
religion (shamanism, totemism, etc.), proto- science (natural history, herbalism, calendrical
record keeping, celestial reckoning), and technology (tools and textiles). It is within the
context of this surprisingly sophisticated intellectual ferment that we begin our enquiry
into the discovery of sex.Barriers to Understanding Sex in Humans During the Ice Age
It has been argued that, because hunter- gatherers of the Upper Paleolithic typically con-
sisted of small nomadic groups of about twenty- five individuals, their survival as a group
depended on restricting their population size. Did the need to control population size
necessitate some form of birth control? If so, the survival of these hunter- gatherers might
have depended on their discovering the role of the male in childbirth, as well as techniques
to prevent or counteract pregnancy. John M. Riddle reviewed the evidence that effective
herbal contraceptives and abortifacients were employed by women as early as the Bronze
Age in Egypt and concluded that some of the treatments were scientifically plausible.^4 For
example, in Libya, from about 600 bce to the first century ce, the city of Cyrene grew
wealthy exporting vast quantities of the herb Silphium, a now- extinct member of the pars-
ley family, largely because of its reputation as an effective contraceptive and abortifacient.
The herb was even featured on Cyrenean coins. Timothy Taylor has speculated that simi-
lar herbal contraceptives and abortifacients may have originated thousands of years earlier,
in the Upper Paleolithic.^5 However, there is no evidence that effective herbal methods of
population control were known during the Ice Age, and controlling population size may
not even have been necessary under Ice Age conditions. The lifestyle of hunter- gatherers
may have been sufficiently stressful to reduce the number of pregnancies without recourse
to artificial measures.
One way in which population growth might have been controlled unconsciously is
by prolonging the period of breastfeeding beyond infancy. According to Luigi Luca and
Francesco Cavalli- Sforza:The hunter- gatherers of earlier times were presumably like those of today, who have
an average of five children, one about every four years. A four- year gap means that the
parents can always carry the youngest child on their backs or in their arms, while the
older ones are already able to walk at a reasonable pace. Longer gaps also mean that