Giant flamingos, enormous zebras and coastal giraffe — our ancestors in the southern Cape had unusual neighbours by today’s standards, judging by the tracks they left in the sand.
Hundreds of recently discovered fossilised track-ways have allowed scientists to turn back the clock to the time of the first modern humans, with surprising results.
A new study of tracks at six new sites points to as yet uncatalogued bird species, adding to a growing list of extinct animals such as the Cape giant horse and long-horned buffalo.
Analysis of the track size, depth and angle has revealed not only the animal’s size but how it moved, showing evidence of telltale flamingo “stomping” — searching for food with webbed feet — and signs of what appear to be a super-sized crane. A study published last year found evidence of an unusually large lion and two humans immortalised while jogging down a dune.
“The recent work indicates that some Pleistocene [400,000 to 35,000 years ago] birds were larger than their extant relatives, and suggests that there were Late Pleistocene extinctions,” said lead author Charles Helm.
“There is no evidence in the body fossil record to support either of these notions, so this is an example of ichnology [the study of fossilised tracks] providing novel information.”
Studying such sand fossil sites, called aeolianites, allows scientists to match ancient tracks with bone fossils excavated from the first human homes, braai places and picnic sites. In this way, researchers gain a clearer picture of what life was like when early humans started acting more like modern humans about 100,000 years ago in a small coastal strip near today’s Mossel Bay.
This “cultural revolution” featured the first rock art and tool-making and is of particular interest to scientists trying to figure out how and why anatomically modern humans became brainier.
• 400,000 years - The age of the oldest fossilised tracks in the southern Cape
• 100,000 years - The age of oldest human “cultural” sites
— in numbers
Many scientists believe it had a lot to do with the abundance of wildlife, in particular seafood in what has been nicknamed the “African Eden” — a wide coastal plain near Cape Agulhas that is now underwater.
The conditions were also perfect, as it turned out, for capturing tracks of wildlife walking through wet sand or marshy areas between dunes. The tracks were filled by wind-blown sand, covered up, then exposed after thousands of years by wave erosion.
“Being the first to see some extinct big animal’s tracks for the first time after the animal made them so long ago is amazing,” said Jan De Vynck, director of the African Centre for Coastal Palaeoscience at Nelson Mandela University.
“It is a real treasure hunt and you never know what could be around the next bend. We’ve had so many discoveries around the next bend that it becomes infectious.”
Helm added: “There is a sense of awe and wonder at knowing with absolute certainty that you and your colleagues are the first to see something that was recorded on dunes and beaches so long ago. And also to know that what you have found is so ephemeral, and will not last long once exposed.
“The wonderful flamingo track site mentioned in our paper, with globally unique feeding traces, was totally obliterated in a recent storm surge.”
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