Ecobotanical Contexts for African Hominids, by O’Brien and Peters, was published in a book edited by J. Desmond Clark entitled Cultural Beginnings: Approaches to Understanding Early Hominid Life-Ways in the African Savanna.
O’Brien and Peters describe the work they are doing on a project called “Survey of the Wild Edible Plants of Africa”. The point of the survey is to assemble as much information as possible on plant species used by baboons, chimpanzees, and humans in Africa. The eventual inclusion of plants used by gorillas was also mentioned.
At the time of the paper, O’Brien and Peters had accumulated dietary and ecological information on 1,500 species of edible plants, 75% of which were utilized by humans. They go on to say:
One surprise was that at least half (45-55%) [of about 461 genera- afarensis] of the genera exploited by each of these primates is exploited by one or both of the others… Thus our study systematically documented for the first time that a high degree of potential competition for plant foods exists (existed) for these primates. This overlap alerts us to the dietary importance of a more restricted subset of plant food genera, and the degree of potential competition that results from common dietary needs and patterns of exploitation.
They also looked at seasonality and dietary quality of plant foods available. In particular, they mention the use of underground storage units. Some of which are toxic – baboons seem to be able to de-toxify them though. I’ll get back to another plant they discuss shortly.
O’Brien and Peters also provide a case study of Makapansgat. After a brief synopsis of the geography, climate, and ecology of the area they get down to business (this is a rather longish excerpt):
This leaves us with an intriguing ecological question: what were the hominids at the Makapansgat Limeworks and Cave of Hearths doing in the Highlands? With regards to the australopithecines, Peters and Maguire (1981) concluded that the highlands would have been visited primarily during the late wet season, when relatively numerous plantfoods were available, and that the difficulty may have been experienced in occupying the highlands during the dry season when plant foods would be restricted mainly to underground parts, suspected to be more numerous in the lowlands.But an hypothesis of wet season utilization of highland plant foods by australopithecines suffers from the fatal flaw that it implies the abandonment of the more fertile and fruitful Nyl River Valley during the time of year when it is most productive.
An alternative hypothesis (J. Maguire, pers. comm.) is that australopithecines in the brecias are the remains of the meals of larger carnivores that were present there, particularly the striped and giant hyenas; perhaps also the sabertooth cats, and/or leopards (not found in the grey brecias). The foraging area for these large carnivores could easily have included eastern portions of the Nyl River Valley. This hypothesis is consistent with the fact that the australopithecine remains represent an extremely minor fraction of the total faunal assemblage in the grey brecia at the limeworks.
An additional and largely complementary hypothesis helps to round off this picture for the australopithecines. During extended droughts the lower reaches of the streams feeding the Nyl River, and the river itself, probably dried up, as observed historically. There is still water in the small streams, seeps, drips, and springs of the highlands, however, and under this interpretation some of the australopithecines that moved into the highlands were subsequently introduced into the cave deposits by the larger carnivores (as mentioned above) during these periods of drought.
One of the interesting things about reading some of the older literature is the way it sometimes resonates with current concerns. We saw that earlier in O’Brien and Peter’s discussion of underground storage organs – something a lot of anthropologists are looking at. Another is When O’Brien and Peter’s mention the distribution of Sclerocarya birrea – a fruit high in vitamin C which contains a nut like oil seed. You can read about why that might be important here.
All in all, the paper is an interesting attempt at looking at early hominid foraging behavior…