Updates on Efforts to Preserve 3.6 Million-Year-Old Footprints Threatened by Climate Change

The St Andrews School of Earth and Environmental Science is heading a project dedicated to protecting and preserving the Laetoli footprints, the oldest evidence of human ancestors walking on two feet. The historical site is at risk for high levels of erosion, caused by the increase in rainfall and storms in the region.

The footprints were identified in 1978 by a team led by paleoanthropologist Mary Leakey at Laetoli, which is located about 45 kilometres south of the Olduvai Gorge in Tanzania. The footprints are estimated to be about 3.6 million years old, dating back to the Pliocene epoch —  a geologic time scale that includes findings from 5.333 million to 2.58 million years ago. 

The footprints were preserved in a layer of ash from a nearby volcanic eruption. After the ashfall, the rain turned the ash into a wet, cement-like consistency. Hominins, the tribe that includes Homo sapiens and other closely related species, walked across this surface, leaving their footprints in the wet ash. The ash later dried and hardened, and additional layers of ash and sediment covered the footprints, preserving them for millions of years until they were uncovered by researchers. The species is generally attributed to Australopithecus afarensis, the same species as the famous “Lucy” skeleton discovered in Ethiopia. 

Based on these findings, researchers were able to identify early social behaviour and pinpoint a more specific period when bipedalism — when hominins began walking on two feet — began. The footprints were made by at least three individuals walking together, pointing to early patterns of socialisation and group travel in our ancestors. Their big toes were aligned with the rest of their feet, indicating that they were more similar to modern humans than to apes, whose big toes resemble thumbs to assist with climbing and grasping. Researchers could also characterise the gait as a heel-strike, in which the heel hits the ground first, followed by a toe-off, where the toes push off at the end of the stride.

Professor Richard Bates from the School of Earth and Environmental Science is leading the project put in place to protect the historical site. In partnership with the British Council’s Department of Culture, Media and Sport, the Cultural Protection fund is allocating more than £2 million to the protection and preservation of 22 cultural heritage sites, including the Laetoli footprints. His team has partnered with the Tanzania Department of Antiquities, the National Park Authority, and the University of Dar es Salaam to train Tanzanian staff in digital documentation and recording techniques. 

Digital documentation is integral to determining which methods of protection will be most effective against storms and rainfall, while also capturing a digital version of the footprints in case they erode further or disappear completely.

“New sites were found that had recently been exposed due to the increase in erosion,” said Bates. “These have been digitally captured so that we have a permanent record before they are lost. The training will ensure that all future sites are captured by local staff on site.” 

In more technical terms, the teams used multispectral drones to map out the area, and then backed it up with electromagnetic surveying on the ground. Bates noted that they were able to collect artefacts including “bone fragments of various animals, flint, basalt, and quartz tools from both early and middle Stone Age societies.”

“Unfortunately, unknown to us or our in-country team, the government received a Chinese grant and decided to build a structure over the main footprint site so that visitors could see the footprints better and the prints might be better preserved,” Bates explained.

“It is unlikely that this structure will achieve this, and further, in building it, they have likely destroyed places which could have contained footprints,” he added. “This is a tragic loss that could have been avoided if the government had consulted Tanzanian experts.” 

The importance of protecting sites like these goes beyond mere scientific preservation — the loss of the Laetoli footprints to erosion would have insurmountable repercussions for cultural heritage in Tanzania. In addition to digital documentation, this project also focuses on collecting local stories, myths, dances, and rituals connected to the historical site. While footprints may erode due to climate change, the project aims to at least preserve the cultural heritage that the site holds. 

The setbacks in this project point to the importance of listening to indigenous and local experts when making decisions about cultural and historical sites. By involving the local community and ensuring their expertise and knowledge are at the forefront of preservation efforts, this project aims to protect the Laetoli footprints while also fostering a sense of ownership and pride among the Tanzanian people. This collaborative approach helps to ensure the long-term success of preserving such a significant heritage site.

Image from Wikimedia Commons