The African rail (Rallus caerulescens) is a handsome bird, with a blueish breast, red legs, eyes and bill, prominent barring on the flanks, chestnut upper parts, and long toes. It also has a characteristic trilling call. This wetland dweller is only found in sub-Saharan Africa, with a concentration in South Africa's Western Cape province.
The species is one of about 140 members worldwide of the Rallidae, the bird family that includes coots, moorhens, gallinules, rails, crakes and flufftails. In southern Africa there are about 15 representatives of the family.
In science, a "holotype" is the type specimen upon which the description and name of a new species is based. These are usually preserved or described specimens. The African rail is unusual in this regard: the species holotype is a 1773 watercolour painting by Georg Foster, now housed in the Natural History Museum in London.
Foster was an artist on board British explorer Captain James Cook's second expedition (1772-1775), which aimed to determine if a great southern continent, "Terra Australis", existed. En route to the southern ocean the expedition stopped at the Cape of Good Hope (now Cape Town), where Foster created the painting.
Now we believe we've found a far earlier representation of the species. We are members of the African Centre for Coastal Palaeoscience at South Africa's Nelson Mandela University, where we study fossil tracks, traces and images. In a recent research article, we described what we interpret as a painting of an African rail, found on the walls of a rock shelter in the Western Cape, south of the Langeberg range of mountains.
At its longest it measures 20cm; it is the largest image in a panel of rock art by a San artist that includes probable images of bees, humans, an aardvark, antelope and plants. While it is not possible to establish the exact age of the rock art, it likely dates back centuries or even thousands of years.
If our interpretation is correct it would almost certainly predate Foster's holotype image. It would also underscore the depth of indigenous knowledge, exemplified by San people who were the original indigenous inhabitants of the region, and who left a remarkable legacy of rock art.
The rock painting
The San were (and remain) accomplished ornithologists (bird experts). Western explorers have related how the San had names for as many as 68 out of 76 species identified during a single day.
The San also considered the thought processes and values of birds to be similar to those of humans, and thought that birds would react to many situations in the same way that humans would. The artist who created this painting has captured the "giss or jizz" (an acronym of "general impression of size and shape") of the African rail, showing its widely spaced feet and forward-angled legs.
Whereas most examples of San avian rock art, such as depictions of kingfishers, swifts, vultures or herons, can only be identified to family level, we contend that identification to species level is possible in this case.
This is exemplified by the 14 sub-parallel bars on the flanks and under the tail coverts that closely resemble the pattern in the African rail. Such prominent barring does not occur in any other member of the rail family in the region.
Half-human, half-bird
However, the image does not simply depict an African rail, and this hints at a spiritual dimension to the purpose of the painting. Often San rock art images take the form of therianthropes, which are half-animal, half-human forms. The term "avianthrope" is used to describe images that contain both birdlike and human features.
There are at least two examples of this in the African rail image. First is the absence of the bill, which gives the image a more human appearance. Second is the orientation of the toes. The African rail has long toes, three pointing forward and one pointing backwards. In the San image four or five forward-pointing digits are depicted, imbuing it with human hand-like characteristics.
We considered that the absence of the bill might have been due to the disappearance of pigment, and that the pattern and number of the toes might represent an artistic error. But we rejected these notions in favour of the artist deliberately creating what might be mistaken for anomalies and essentially creating a "rail-person".
Why would a San artist wish to create an image of an African rail? We cannot claim to understand the mind of an individual artist and can only speculate.
However, we noted in our paper that the rock shelter lies very close to the African rail's preferred habitat, a wetland with reedbeds. And the bird's distinctive features and call would have rendered it easily recognisable and memorable. Red was an important colour for the San due to its links to blood.
Furthermore, as with some other rails, the African rail can compress itself laterally and become almost two-dimensional. This is the origin of the term "as thin as a rail" and its unusual ability allows the rail to pass easily between vertical reeds and disappear quickly into a reedbed. We suggested that the "rail-person" may have been a conduit for the San to the spirit-world beyond the reedbed. A similar theory has been advanced for avianthropes of swifts or swallows entering a spirit-world behind the rock face.
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A rich culture and worldview
Tragically, the San were relentlessly pursued, persecuted and killed by various colonists, mainly in the 18th and 19th centuries. They were essentially wiped out from many parts of southern Africa.
However, the richness of their culture and worldview is now widely recognised. They were among the finest trackers the world has known. San master-trackers from Namibia are now assisting our research team with fossil track recognition, and have recently identified, among other discoveries, fossilised ostrich tracks which would otherwise have been missed.
The African rail painting which we have described can take its place as the oldest known example of its kind, and can provide a window into the world of the knowledgeable field ornithologists of a distant past.
Charles Helm, Research Associate, African Centre for Coastal Palaeoscience, Nelson Mandela University
Andrew Paterson, Research associate, African Centre for Coastal Palaeoscience, Nelson Mandela University
Renee Rust, Research fellow, Department of Geography, Archaeology & Environmental Studies, University of the Witwatersrand; Research Associate, African Centre for Coastal Palaeoscience, Nelson Mandela University
