As shallow lakes in a hot climate, their water temperatures can reach as high as 106 degrees Fahrenheit (41 degrees Celsius). Both are terminal lakes that do not drain out to any river or sea they are fed by hot springs and small rivers. Lake Natron is one of two alkaline lakes in that area of East Africa the other is Lake Bahi. The flamingos' nests are built on small islands that form in the lake during the dry season. Some tracks exposed by erosion on one part of the site lead to areas still covered by sediment, offering the promise of further prints.Įxcavation is on hold for the moment though, because the site is vulnerable to erosion and researchers are hoping to come up with a conservation plan before continuing work.During breeding season, more than 2 million lesser flamingos ( Phoenicopterus minor) use the shallow lake as their primary breeding ground in Africa. Hatala acknowledged the theory remains just that for now, and more may eventually be revealed by further excavations at the site. "But the opportunity to witness the behaviour through this direct snapshot is exceptional." "The behaviour itself isn't surprising to see in a human group from this time period," said Hatala. The make-up of the ancient group implied by analysis of the footprints led the team to theorise that is what the group of women may have been doing. In modern-day hunter-gatherer communities, large numbers of women rarely move in a group, unaccompanied by children or a similar number of adult men, except when foraging for food. The make-up of the travelling group also offers clues about their lifestyle. "However, skeletal material from this time period and region is generally scarce, underscoring the value of the relatively large sample of anatomical data that is preserved on the Engare Sero footprint surface." Skeletons from around the period in east Africa "have suggested generally tall and long-limbed body builds," said the study published Thursday in the journal Nature Scientific Reports. The trackways also allowed the researchers to extrapolate the height of the people who made them, revealing some comparatively tall men among the group, including one standing an estimated 1.83 metres. There is some room for error, they acknowledge, with the possibility that the smaller feet and shorter strides they attributed to women could in some cases belong to children or adolescents of either gender. The research team focused on "distinct trackways" where they could clearly discern stride distances and footprint length, looking for more clues.īased on the size of the prints and the stride lengths, they determined the group included four adult men, 19 adult women and two younger boys. That, combined with other evidence including the lack of overlap on footprints, strongly suggests the impressions were made by a group travelling together at the same time, rather than by individuals moving across the same area at different times. The prints were made in wet volcanic mudflow, which would have dried quickly into a hard surface, said Hatala. Three years of additional excavations revealed hundreds more prints, made by humans but also animals such as zebra and buffalo. In 2009, when the research team first visited the site - discovered by a local Maasai community - just 56 footprints were visible, exposed by natural erosion. "However, we have also been able to learn some really interesting things from these direct windows to the behaviour of the group that walked across the footprint surface."Īnalysing the footprints was a complex process. "Given the rarity and value of this variety of fossil evidence, part of what makes our discovery exciting is its magnitude, with over 400 footprints preserved on the same volcanic ash surface," he told AFP. "Sites like Engare Sero form over very short time intervals, and so they capture snapshots in time of ancient humans moving across their landscapes," said Kevin Hatala, assistant professor of biology at Chatham University, who led the research. It's the largest group of human footprints ever found in Africa, and offers a glimpse at what humans in the so-called Late Pleistocene period looked like, as well as how they may have gathered food. The group of more than 400 footprints was made sometime between 5,000 and 19,000 years ago at a site called Engare Sero, south of Tanzania's Lake Natron. The footprints they left behind are now offering insights into ancient human life. Thousands of years ago, a group of people took a walk in what is now Tanzania.
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