Fossil tracks and trunk marks reveal signs of ancient elephants on South Africa’s coast

A whole bunch of 1000’s of years in the past, South Africa’s Cape south coast regarded very completely different. Among the species that roamed this space are actually extinct; others developed over the millennia and their fashionable descendants inhabit completely different areas — some distant, others close by.

For example, within the nineteenth century, a inhabitants that got here to be generally known as the “Knysna elephants” (a reference to the closest massive city) had been essentially the most southerly group of elephants in Africa. Over time they turned the one free-ranging elephants in South Africa. Their numbers had been decimated by the ivory market and habitat transformation. Proof signifies that just one elephant, an grownup feminine in her forties, stays.

Now, about 18 km from the realm that lone elephant occupies, we now have discovered new proof of her historical ancestors within the type of fossil tracksites from the Pleistocene Epoch. These websites fluctuate in age from 400,000 to 35,000 years. The tracks, preserved in aeolianites (the cemented stays of dune surfaces) and cemented seaside deposits, dovetail with more moderen proof that elephants traditionally made widespread use of open areas within the area.

Together with elephant tracks from websites on the Cape south coast, we recognized what seems to be the primary instance within the world hint fossil document of elephant trunk-drag impressions. We interpret the impressions in query as having been made by an elephant both dragging its trunk or dragging one thing it was gripping in its trunk. These marks are according to the form of trunk-drag traces described in monitoring manuals and on numerous web sites.

The extant African bush elephant (Loxodonta africana) — the Knysna elephant belongs to this species — is understood to point out trunk-dragging behaviour below quite a lot of circumstances, together with musth, sporadic intervals throughout which bull elephants are significantly aggressive.

Our latest article targeted on the 35 elephant tracksites, that are among the many greater than 300 vertebrate Pleistocene tracksites that we now have recognized alongside a 350km stretch of the shoreline since 2008. Such fossil tracksites can inform us many issues about what occurred on these historical dunes and seashores, and the traditional setting that the elephants roamed.

For one, they provide insights into the possible historical past of the Knysna elephants, suggesting that the remaining elephants retreated into dense afrotemperate forest for defense in latest centuries, the place hunters had problem discovering them.

The tracksites are additionally essential as a result of elephants are ecosystem engineers. Their presence could have large-scale results on the panorama: for instance, they will rework woody habitats to extra open habitats. They could effectively have facilitated the event and upkeep of the mosaic of woodland and grassland habitats that characterised the massive, now-submerged Palaeo-Agulhas Plain through the Pleistocene.

Massive tracks

Fossil elephant tracks can take a lot of types. Typically they’re acquainted depressions; typically they seem as pure casts, representing the layer that crammed within the tracks and, so, protruding down from the ceilings of overhangs. They may also be seen in profile in cliff outcrops.

Elephant tracks, predictably given the animals’ dimension, usually deform underlying layers. Typically, when these tracks might be discerned in profile in a number of successive layers, conclusions might be drawn about repeated use of an space over time. In some instances, elephant tracks on seashores had been precursors for the formation of potholes. In locations they’ve been eroded into weird shapes, which seaside hikers admire and go by with out understanding their intriguing origins.

Analogies might be drawn between Pleistocene elephant tracks and Mesozoic dinosaur tracks: in each eventualities they had been the most important tracks of their time, made by the heaviest creatures. In truth, it seems that the elephant tracks we described at one website, measuring as a lot as 70cm in diameter, are the most important tracks ever recognized because the “Age of Dinosaurs”.

The elephant trunk-drag website was recognized on an aeolianite floor within the Goukamma Nature Reserve, round 500km east of Cape City. There have been additionally tracks of the extinct long-horned buffalo and of smaller buck species, two coprolite websites – that’s, fossilised dung – and small carnivore tracks, alongside quite a few examples of elephant tracks.

The positioning is barely uncovered at low tide, being topic to intense wave motion throughout excessive tides and storm surges. It’s also normally lined by metres-thick layers of seaside sand, so we had been lucky to seek out it throughout a uncommon event through which it was uncovered.

Right here, beside an elephant trackway comprising 13 tracks which traversed a cemented dune slope, we encountered a “serpentine” sequence of two lengthy, barely curved groove options with an outward convexity, one on either side of the trackway. Displacement rims had been current; these point out {that a} compressive pressure had brought on the grooves. In a single spot we might inform that the grooves had been registered first, after which the tracks, according to how elephant footprints usually are superimposed on components of trunk-drag impressions.

We thought-about interpretations aside from trunk-drag impressions, however any different prospects seemed to be actually distant.

Filling in gaps

There aren’t any physique fossils of elephants from this time interval, so the obtainable details about how these gigantic animals moved via the traditional landscapes at present relies upon completely on the monitor document.

Every elephant tracksite we establish evokes a way of surprise at how the tracks — and on this case, the trunk-drag impression — survived, in opposition to the percentages and are actually amenable to our interpretation, as we attempt to learn the story the rocks inform us.

Charles Helm, Analysis Affiliate, African Centre for Coastal Palaeoscience, Nelson Mandela College

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