It was never an easy life for the early ancestors of human beings and recently ancient eggshells have thrown light on this. The evidence thrown up by these shells suggest that they had dealt with climate change of extreme nature during those times.
The study goes on to reveal that there were areas in South Africa which long ago were wetland and grassland even though today we find them dry and populated sparsely. The period of this contrary scene is 250,000 to 350,000 years ago – a crucial period in the evolution of humans.
An article which appeared in sciencedaily.com talks about this study in which Philip Kiberd and Dr Alex Pryor, from the University of Exeter, studied isotopes and the amino acid from ostrich eggshell fragments. These shards were dug out at the Bundu Farm located in the upper Karoo region of Northern Cape which was an early middle Stone Age site.
Significantly, this site dates back to 250,000 to 350,000 years and is one of the small number of sites linked with a period in which Homo sapiens appeared.
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Fresh findings which have come to the fore along with other evidence – from fossil animal bones – points out that communities of Home sapiens shared this area with groups of other animals like wildebeest, small antelope, hippos, zebra, baboons besides the extinct type of Megalotragus priscus and Equus capensis. Apart from sharing this area with them humans also hunted them along with other animals like lions and hyenas.
Following this period of equitable climate and environment there was a change. From the eggshells and other evidence it is indicated that wetter and cooler climates yielded place to aridity which increased over time. This crucial changeover of the climate – from wet to dry – had its effect on turnover and evolution of all species including that of humans.
Published in the South African Archaeological Bulletin, this study, revealed that isotopic data extracted from eggshells of ostriches that are found commonly on the southern Africa archaeological sites, is a feasible option for those open-air sites that are older than 200,000 years.
By grinding a miniscule portion of the eggshells to powder, experts are able to analyse and also put a date to the shell. This allows them to fix the climate and environment of the past.
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How do the shells disclose details of the past climates? It is possible since these birds eat freshest grasses and shrub leaves which are found in their location, which means that their eggshells tell us about their diet.
Importantly, as the ostrich eggs are laid during the breeding time for a short window, the details which are present in the eggshells help us to get a picture of what the situation, including that of the prevailing climate and environment, was at that precise time period.
The place from where the eggshells were found, Bundu Farm, is a farm that is located 50 kilometres from the nearest town, and has a dry semi-desert environment.
It was in the late 90s that the place was excavated for the first time. The material obtained from there was kept at the McGregor Museum, Kimberley.
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What makes this particular study crucial is that it enables filling up of the gap in knowledge pertaining to this area of South Africa and helps to put the Bundu Farm site on the map.
Elaborating on the study which he led, Kiberd, observed: "This part of South Africa is now extremely arid, but thousands of years ago it would have been Eden-like landscape with lakes and rivers and abundant species of flora and fauna. Our analysis of the ostrich eggshell helps us to better understand the environments in which our ancestors were evolving and provides an important context in which to interpret the behaviours and adaptations of people in the past and how this ultimately led to the evolution of our species.”
