The Cape south coast of South Africa is a scenic region, known for its rugged cliffs, sandy beaches, and rich biodiversity.
But beneath the surface of this landscape lies a hidden treasure: the fossil tracks of Pleistocene vertebrates, some of which belong to extinct megafauna that roamed the area more than 100,000 years ago.
These tracks, preserved in ancient sand dunes, offer a rare glimpse into the life and ecology of the animals that inhabited this region during the last interglacial period, when the climate was warmer and wetter than today.
They also complement the scarce body fossil record, which mainly consists of bones and teeth found in caves and river deposits.
How to find and study fossil
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Fossil tracks are formed when animals leave impressions of their feet, claws, tails, or bodies on soft sediment, such as sand, mud, or ash.
These impressions are then buried by more sediment and eventually lithified, or turned into rock, over time.
Fossil tracks are also known as ichnofossils, or trace fossils, because they record the behaviour and activity of the animals, rather than their anatomy.
These are often exposed by erosion, weathering, or human activity, such as quarrying or road construction and can be found on bedding planes, or horizontal layers of rock, that are visible on cliffs, outcrops, or boulders.
To study fossil tracks, researchers measure, photograph, and map the tracks, and compare them with the tracks of living or extinct animals to identify the trackmakers.
They also use various dating methods, such as optically stimulated luminescence (OSL), to determine the age of the tracks and the sediment that contains them.
What fossil tracks tell us about the Pleistocene fauna of the Cape south coast
The Cape south coast has several fossil tracksites that date from the late Pleistocene, between 128,000 and 116,000 years ago.
These tracksites are located in aeolianites, or fossilized sand dunes, that were deposited during Marine Isotope Stage 5e, the last interglacial period.
The tracksites contain a variety of tracks and traces, such as burrows, swim traces, and invertebrate trails, that reflect the diversity and complexity of the Pleistocene ecosystem.
The most remarkable tracksites are Roberts Rock and Megafauna Rock, two large boulders that were found about 400 metres apart, east of Still Bay.
These rocks contain tracks of four members of the Pleistocene megafauna: elephant, long-horned buffalo, giant Cape horse, and rhinoceros.
These animals were much larger than their modern relatives, and some of them are now extinct or extirpated from the region.
The tracks show that these animals moved in herds, grazed on grasses and shrubs, and interacted with each other and their environment.
Other tracksites on the Cape south coast revealed the presence of large reptiles, such as crocodiles and monitor lizards, that are no longer found in this area.
These tracks and traces indicate that these reptiles inhabited freshwater habitats, such as rivers, lakes, or marshes, and occasionally ventured onto the dunes.
They also suggest that the climate was more humid and tropical than today, allowing these cold-blooded animals to thrive.
The fossil tracks of the Cape south coast are a valuable source of information for palaeontologists, archaeologists, and ecologists, who can use them to reconstruct the past biodiversity, behaviour, and ecology of the Pleistocene fauna.
They also provide a unique opportunity for the public to appreciate and learn about the natural history of this region, and to understand the impact of climate change and human activity on the evolution and extinction of species.
The fossil tracks are, however, vulnerable to natural and human-induced threats, such as erosion, vandalism, or development, and require conservation and management to ensure their preservation for future generations
