Little Foot may not be as old as thought
A single rock was of an entirely different age than any other sample taken. Now, scientists are questioning the age of the skeleton because of that variation.
Scientists have suggested that Little Foot – the almost complete skeleton of an Australopithecus Prometheus (semi-human) is not necessarily as old as those who gave it an age think it is.
In an article in a weekly scientific publication called Nature, a group of scientists (Granger et al) who took a lot of samples of stones embedded around the skeleton, which was found in the Sterkfontein Caves, and tested their age using a technique known as cosmogenic nuclide dating argued that Little Foot is about 3,6 million years old, as determined by the average age of the stones initially examined when the skeleton was found.
Cosmogenic nuclide dating, or measuring the amount of radiation in rocks, is one of three processes used by scientists to determine the age of rocks, or measure how long they have been underground, and to determine the age of the fossils found in the Cradle of Humankind. Rocks absorb radiation when exposed to the sun. When they stop being exposed to the sun, for instance, when they fall into caves, the rocks start to release the radiation. The more radiation released, the longer the rocks have been underground and the older they are.
Most of the rock samples taken from around Little Foot indicated that the stones and fossils in the same sediments were deposited underground about 3,6 million years ago. However, a single rock was of an entirely different age than any other sample taken. This has caused other scientists to question the age of the skeleton.
In the 2017 edition of the Journal of Science, Professors Jan Kramers and Paul Dirks used this single sample to question the effectiveness of the dating process and therefore the age of Little Foot too.
“This goes to show that one single sample can be used to create an entire new story about Little Foot,” said Dr Dominic Stratford, senior lecturer in archaeology at Wits University and director of research at Sterkfontein Caves. “However, this is still a hypothesis that needs to be proven by gathering different forms of evidence. We are in the process of preparing a response to the hypothesis that will be released soon.”
It is good to question the dating because it provides alternative hypotheses that have to be tested and means that we need to look more closely at all the different types of evidence and develop clearer interpretations of Little Foot’s history.
“Along with Mrs Ples, Little Foot is one of the iconic finds from the Sterkfontein Caves, which in 2016 celebrated 80 years of ongoing research,” said Lindsay Marshall, the curator at Maropeng, the official visitor’s centre for the Cradle of Humankind World Heritage Site. “Our visitors want to know all about Little Foot and its importance in the hominid fossil record. We are in the fortunate position to be able to share with the public the dynamic research and debate that is going on. The complexity of the dating is just one example of this.”
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