Fossilized ancient ostrich eggshell shines a light on extreme climate change

Shane McGlaun - Jul 11, 2021, 10:07am CDT
Fossilized ancient ostrich eggshell shines a light on extreme climate change

The ostrich has been around for thousands of years, and researchers have found evidence in ancient ostrich eggshells about extreme climate change that faced the ostrich and the early ancestors of humans. In the research, scientists found parts of the interior of South Africa that are dry and sparsely populated today were wetland and grassland between 250,000 and 350,000 years ago. Those time frames match a key time in human evolution.

In their study, researchers investigated isotopes and amino acids from an ostrich eggshell fragment excavated from the early middle Stone Age site of Bundu Farm in the upper Karoo region of the Northern Cape. The site is said to be one of the few archaeological sites that have been dated to 250,000 to 350,000 years ago in southern Africa. That period of time is linked to the earliest appearance of communities with the genetic signatures of Homo sapiens.

Data gathered from the actual fragment was compiled along with other evidence from fossil animal bones that communities in the region lived along with herds of grazing wildebeest, zebra, small antelopes, hippos, baboons, and other extinct species. The ancient Homo sapiens also hunted along with carnivores, including hyena and lions.

The study data suggest that around 200,000 years ago, cooler and wetter climates gave way to increasing aridity. That process of changing wet and dry climates is recognized as driving the turnover and evolution of multiple species, including Homo sapiens. The study proves that extracting isotopic data from an ostrich eggshell, which are commonly found in archaeological sites in southern Africa, is a viable option in open-air sites greater than 200,000 years old.

The technique grinds a small part of the eggshell to a powder and allows experts to analyze and date the shell, giving them a fix on climate and environments of the past. Ostrich eggshells are good for investigating past climates because the creatures eat the freshest leaves of shrubs and grasses available in their environment, so the eggshell composition reflects their diet.


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