Researchers Uncover Rare Aardvark Trace Fossils Along South Africa's Coast
- Apr 2
- 10 min read
New Study Describes Discovery and Identification of Rare Aardvark Trace Fossils
Last year, I was trying to identify a rather odd-looking bone, a phalange (finger/toe bone). I walked from shelf to shelf, comparing my little archaeological find to bones collected from various canines, felines, bucks, and monkeys, but none of them matched.
A friend of mine and a visiting professor were equally stumped until a Frenchman, who actually specializes in birds, had a look at the bone.
‘If it is really weird, and nothing else matches, it is probably an aardvark.’
We went to the only aardvark skeleton in the entire collection, and lo and behold, the bones matched. Thank you, kind Frenchman!
Aardvarks (Orycteropus afer) can be found in many archaeological sites across southern Africa, and today, they still have a wide distribution. However, while their body fossils are rather substantial, their trace fossils are scarce.
A study conducted by Dr. Charles Helm and colleagues recently possibly identified five large burrows and one fossil track site to aardvarks. The five burrow sites and potential track site represent some of the only trace fossil evidence of these ‘master diggers’ from the Pleistocene. Helping fill a significant gap in the aardvark trace fossil record
Let me Introduce the Earth-Pigs
Aardvark also known as antbear or erdvarks, belong to the Order Tubulidentata and the Family Orycteropodidae. Their name directly translated from Afrikaans, means ‘earth-pig’. While their Latin name translates to ‘burrowing foot of Africa’. Today, Tubulidentata is the only mammalian order containing a single extant species. However, the genus Orycteropus does contain some extinct species.
They are rather odd-looking creatures if you’ve never seen one before, with a long ‘pig-like’ snout, large ‘donkey-like’ ears, and a long tapering tail. They look a bit like an armadillo, a pig, and I guess a donkey had a child.
Despite being widely distributed across southern Africa, they are not common anywhere. In fact these creatures are a rare sight, likely due to their nocturnal habits and solitary lifestyle.
This, too, contributes to there being relatively few specimens in any given bone collection (such as the collection I was using, which only had the one skeleton).
Aardvarks can weigh up to 65 kgs and tend to travel around 2km per night in search of food, although distances of up to 8.4 km have been recorded at the Tussen- die Riviere Nature Reserve (Free State, South Africa).
Sometimes, these animals fall prey to larger predators such as lions, hyenas, and leopards, as well as some Indigenous people who hunt them for their meat or for ritual purposes. According to some Shona traditions in Zimbabwe, the aardvark is also of ritual significance. Hence, aardvarks that have been hit by cars soon see themselves stripped of their digits and snouts by traditional doctors.
According to southern African tracking guides the footprints/tracks of the aardvark are very distinct and easily recognizable. Tracks usually measure between 8–10 cm, and leave behind a tridactyl (three-toed) print ending in prominent claws on the forefeet (which have four feet). Meanwhile, hind feet (which have five toes) usually leave tracks that are slightly larger and leave either three or four-toe impressions. In soft soil, a tail drag mark may also be present.
Their burrows, however, are the most characteristic behavioral marker of the aardvark. They can serve as permanent shelters, temporary refuges, or be the result of foraging activities. For foraging activities, aardvarks tend to dig shallow holes into the sides of termite bounds. Temporary refuges may be a few meters deep but rather un-complex. While permanent shelters consist of multiple tunnels and entrances that can extend 5–8 meters deep.
When these burrows are abandoned, other animals typically start to take refuge in them, including warthogs, porcupines, honey badgers, hyenas, snakes, and even birds.
While aardvarks leave behind many easily identifiable traces in their environments, the trace fossil record, which could include tracks, tail impressions, feeding traces, burrows, and even coprolites (fossil feces), is surprisingly scarce.
In fact, to date, only a single, unconfirmed, and undated aardvark burrow may have been identified previously from Simanya on the south bank of the Kavango River in northern Namibia.
The Aardvark Trace and Burrow Fossils
Since 2008, the Cape South Coast Ichnology Project has documented more than 350 Pleistocene vertebrate ichnosites (sites with trace fossils) along a coastline of around 350 km. Recent exploration along the Cape West Coast, Cape Southwest Coast, and Cape East Coast has identified even more ichnosites, most of which are track sites, although some feeding traces and dwelling structure fossils have also been identified. These feeding and dwelling structures have mostly been ascribed to the golden mole or gerbil.
While vertebrate burrows are relatively well discussed in the Karroo regions of South Africa, similar vertebrate burrows, despite being found along the Cape coast, are rarely studied and thus have left a substantial knowledge gap on what made them and when. Information that may enhance or complement existing evidence found in other parts of the archaeological record.
The five burrow sites were identified in five separate areas. Site 1 was documented near Die Kelders, in the Walker Bay Nature Reserve. It consists of three large burrowed cavities with smaller connecting tunnels. Site 2, known as ‘Burrow Bay’, had numerous burrows, including two larger cavities that had been heavily eroded by wind and water.
Site 3 was located only 11 km from Site 2 in an area known as Drietfontein. It consisted of three burrows. After its discovery, a rockfall covered it.
Site 4 was discovered in 2014 in the Goukamma Nature Reserve, and revealed a single large burrow that ended in a large chamber. The site was revisited in 2024 but had been almost completely covered by a large layer of sand that needed to be excavated.
Finally, Site 5 was located in a high cliff in the Woody Cape section of the Addo Elephant National Park. The burrow was situated around 2,5 meters above the ground, although exact measurements of the burrow could not be taken as an Egyptian goose was nesting within the hollow.
(I have Egyptian geese that tend to land on our roof during migration, they are mean-spirited little creatures, and I can only imagine the mother Egyptian goose would not have been too happy with researchers poking around in her pretty little burrow).
Finally, the track site was discovered 3 km east of Site 2 and 8 km west of Site 3. It consists of a single, tridactyl (three-toed) track preserved on the surface of a loose aeolianite (dune limestone) slab at the base of cliffs.
Although none of the sites could be directly dated, optically stimulated luminescence (OSL) dates from nearby sites provided appropriate ages for each site. With Site 1 dated to around 76 ± 5 ka, Site 2 to 134 ± 9 ka, Site 3 to 126–114 ka, Site 4 to 78 ± 5 ka, and Site 5 to 126 ± 8 ka.
Who Made the Burrows and Tracks?
As mentioned above, track and burrows of aardvarks are rare, in fact, no other evidence except the undated and unconfirmed singular aardvark burrow from Namibia exists. It was thus up to the researchers to determine which animal made these fossil traces without being able to compare them to other confirmed aardvark trace fossils.
Beyond the aardvark, various other animals that exist regionally were taken into consideration, including the Cape porcupine, jackals, wild dogs, bat-eared fox, Cape fox, and springhares.
Cape porcupines are prolific diggers and, in fact, are known to dig up and chew on archaeological bone. However, their burrows are typically V-shaped and have smooth upper walls resulting from their quills polishing (abrasion) the surface as they dig, enter, and exit the burrow. This is in contrast to the burrows found by the researchers, which were typically circular and showed no signs of quill abrasion.
Additionally, while porcupines can dig, they often repurpose existing aardvark burrows rather than dig their own. Why build your own home when someone else can do it for you?
Next, the jackals and African wild dogs were taken into consideration. However, these animals do not dig burrows, only use them opportunistically. Other carnivores in the region that do dig burrows include the bat-eared fox and Cape fox. However, this small creature digs similarly small burrows. The fossil burrows were much too large and thus unlikely to have been dug by any type of fox.
The same problem is faced by the final burrowing species in the area, the springhares, which usually only make burrows 18–25 cm in diameter. This is in stark contrast to the fossil burrows, which were sometimes up to 50 cm in diameter.
With respect to the track fossils, some researchers noted that aardvark tracks could sometimes be confused with tracks made by warthogs or bushpigs. However, these species leave didactyl tracks (toe-toed), while the trackways found by the researchers were tridactyl.
This, coupled with the absence of warthogs, bushpig, or antelope tracks in the area, as well as the gait, size, and morphology, made the trackways most likely created by an aardvark.
Combining the Evidence
Now, it is time to combine the evidence; as mentioned before, trace fossils can complement existing evidence. But what existing evidence exists on aardvarks in the area?
The very first aardvark fossil (type fossil) was recovered from the Cape of Good Hope in 1766, and many other body fossils have since been found at other coastal archaeological sites, including Klasies River, Nelson Bay Cave, Sea Harvest, and Eland’s Bay Cave.
The fossils from Klasies, Nelson Bay Cave, and Eland’s Bay Cave have been found in layers dated to the Pleistocene, early Holocene (10–9 ka), and Later Stone Age, respectively.
However, not a single aardvark fossil has been found at the Die Kelders 1 Cave near Site 1, dating to the Middle and Later Stone Age, making the fossil burrows the only evidence of their existence in the region at this time.
Additionally, many of the Sites were found near trace sites of termites and ants, giving circumstantial evidence that the coastal dune systems were suitable aardvark habitats.
Meanwhile, historical evidence includes travelers’ and naturalists’ reports, place names, and rock art depictions. References to the dangers the aardvarks’ burrows posed to riders, wagons, and carts are made in various historical accounts.
For example, a missionary from Mamre in the Western Cape in 1816 describes the risk of injury from burrows close to a blind chief’s dwelling, commenting on the creatures that made them,
‘Earth-hogs had made approaches towards his hut, which they seemed disposed to undermine. Several of their holes were not far off, and being aware of the danger, he made some inquiry about them. We advised him, either to get his people to destroy them, or to remove his hut, as otherwise, before he was aware, he and the old woman that attended him, might be suddenly let down alive into the sepulchral caverns.
These singular creatures are about as large as a common pig. They have a long snout, long sharp claws, very little hair, and a rough skin. Their food is the ants, and probably other insects…The holes made by these creatures are often hid among the bushes, and a huntsman crossing the waste, may meet with an unexpected overthrow, either by falling into them, or by the earth being undermined near the entrance, giving way under the horse’s feet.’ -Reverent C. I. Latrobe, 1818, Journal of a visit to South Africa, page 310
Although rarer, some rock art depictions also exist of aardvarks; these are difficult to date but are estimated to be at least 2,000 years old, although the oldest southern African rock art is as old as 27,000 years old (Apollo 11, Namibia).
The aardvark imagery can be found in the Leeublad site in the Kammanassie Mountains (Little Karoo), Cloete’s Pass (Little Karoo), Sevilla in the Cederberg, and a site in the Langeberg.
The above evidence shows just how prolific aardvarks were in both historic and prehistoric contexts.
But if they were so prolific, why have their trace fossils not been preserved? Well, just as one of the discovered burrows was subsequently covered by a landslide only a few years after discovery, and those at Site 4 were completely covered in a layer of sand, these fossils likely come and go. Coupled with them simply not having been recognized for decades, it makes sense that few have been recorded. Dr. Helm elaborates,
‘Such burrows have come and gone in the fossil record for thousands of years and not been recognized. Now we are privileged to recognize and describe them. But we need to accept that the known sites will be eroded (one of them has already been covered by a landslide), and new ones will be exposed. What is true is that climate change and resulting storm surges are accelerating the rates of erosion and cliff collapse, so we need to be vigilant and revisit areas after such storm events.’
Perhaps with the tentative identification of these aardvark burrows and tracks, more will be identified in the future.
‘We are very lucky in having wonderfully preserved aeolianites and palaeosols here on the Cape coast of South Africa. Aeolianites do occur further north along the African coast as well, and others may well find more aardvark burrows there,’ says Dr. Helm.
A recent study by Dr. Helm and his colleagues describes the discovery and identification of possible aardvark trace fossil sites. These fossil sites provide compelling evidence to confirm the body’s fossil record as well as fill a substantial gap in the trace fossil record for this area and period. It is interesting how aardvarks, which leave such conspicuous features in present and historical environments, are nigh absent from the trace-fossil record.
It would be like future archaeologists being unable to find footprints or gnaw marks of cats, only their bones.
Why are aardvark trace fossils absent from the fossil record? And what else can they possibly tell us about their behavior in the distant past?
References
Helm, C. W., Carr, A. S., Cawthra, H. C., De Vynck, J. C., Dixon, M. G., Gräbe, P.-J., Rust, R., & Stear, W. (2025). Pleistocene aardvark (Orycteropus afer) burrow traces on South Africa’s Cape coast. Quaternary Research, 1–14. doi:10.1017/qua.2024.48
Skinner, J. D., & Chimimba, C. T. (2005). The mammals of the southern African sub-region. Cambridge University Press.
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