The Sahara has expanded about 5,500 years ago and lead ancient herders to chase the rain and grasslands south to eastern Africa. Around 2,000 years back their southward migration started fading away before coming to a stop and archaeologist believe it was done by tsetse-infested bush and disease.
It is believed that the bite of a tsetse fly was responsible spreading the herding of domesticated animals as it caused sleeping sickness and nagana. This is considered to be fatal to bother the herder and the one being herded.
Study co-author Fiona Marshall, PhD, professor of anthropology at Washington University in St. Louis said “This study overturns previous assumptions about environmental constraints on livestock management in a key area for southward movement of early herders. It reveals that the vegetation east of Lake Victoria was then much different than it is today and that ancient grassy environments may have provided an important corridor for herders moving into southern Africa.”
Tsetste flies are known to thrive in dense wooded bush-land and that could have posed threats for transitioning cattle in the region of east Lake Victoria. This theory is contracted by another study which says that around this time, settlements had diets of predominantly grassland vegetation. So it is unlike that tsetse flies would take over that area.
A study on the basis of isotope analysis on tooth enamel extracted from ancient animal remaining confirmed that in the duration of the Gogo Falls settlement, the region was enveloped in extensive grasslands. Between the years of 1,600 and 1,900 Neolithic Elmenteitan herders occupied the GogoFalls settlement with residents enjoying a wide array of diet inclusive of domesticated cattle, wild mammalian herbivores, fish and birds.
Archaeologist one have debated that the settlements dependency on domestic as well as wild food sources was an indication of the damage that tsetse fly infestation must have caused on domestic herds which lead herders to resort to seasonal hunting and accumulating wild foods to make up for herd losses.
Demonstrating the fact that tsetse flies were not an issue during the Gogo Falls this new study proposes that the consumption of both domestic and wild sources of food were a choice than a necessary option for them.
Marshall said. “Our findings challenge existing models that explain the settlement’s diverse diet as a consequence of depressed livestock production related to tsetse flies. Instead of this ecological explanation, our isotopic findings support the notion that herders may simply have interacted with hunter-gatherer groups already living in these areas, adapting to their foraging styles. This suggests that social factors may have played a greater role than previously thought in subsistence diversity during the spread of pastoralism in Eastern Africa.”
“Given such complex environmental interactions in African grasslands today, the question arises whether ancient herders in the Lake Victoria basin helped create grasslands through grazing and fire, or whether they were created and maintained by other ecological and climatological factors,” researchers conclude.
“Herding was the earliest form of African food production and it transformed the lives of local populations of people and animals,” Marshall said.
The research endows with new perspective on the significance of tsetse flies and bushy environments in depressing livestock production and human disease, signifying that grassland distributions in the Lake Victoria basin were not comparable to modern day and those barriers to the southward spread of pastoralism varied more than formerly considered.
“From a broader perspective, the findings expand our understanding of factors that have influenced and contributed to the distribution of modern populations,” researchers said.
