Colours of Wildlife: Cape Grysbok
Created | Updated Feb 25, 2018
Cape Grysbok
Willem is a wildlife artist based in South Africa. He says "My aim is simply to express the beauty and wonder that is in Nature, and to heighten people's appreciation of plants, animals and the wilderness. Not everything I paint is African! Though I've never been there, I'm also fascinated by Asia and I've done paintings of Asian rhinos and birds as well. I may in future do some of European, Australian and American species too. I'm fascinated by wild things from all over the world! I mainly paint in watercolours. . . but actually many media including 'digital' paintings with the computer!"
This is a Cape Grysbok, Raphicerus melanotis, a small but solidly-built antelope that only occurs in South Africa. It is a very close relative of the Steenbok. The name 'grysbok' means 'grey buck' but it isn't very appropriate, since it is reddish-brown rather than grey in body colour, but with white hairs interspersed to give its dense coat a grizzled effect. The Cape grysbok reaches a shoulder height of about 54 cm/21.5" and a bodyweight of about 12 kg. As in the related Oribi, the ewe is slightly heavier than the ram. Only the ram bears the short, straight horns, which are typically about 8 cm/3" long but reaching a maximum of 12.5 cm/5".
An Archaic Antelope
I can't find much information about this antelope, and I haven't even seen it yet, myself. It occurs only in the Western and Eastern Cape provinces of South Africa; I've been in that region only once and didn't luck upon it. Grysboks live in shrubland, thicket or low forest, keeping themselves well hidden. Where people are active, they tend to be nocturnal. Their compact bodies are well adapted at skulking and creeping through dense vegetation. In shape, size and behaviour, the Cape Grysbok is actually almost the model of the original, ancestral antelope, having changed pretty much not at all. Even forty to fifty million years ago there were many similar small browsers in the forests of the northern hemisphere. Initially these lacked horns, but by twenty or so million years ago, antelope-like horns had evolved. About this time antelopes first entered Africa; the group seems to have had its origins in Eurasia. The current wealth of antelope species found in Africa is a result of rapid diversification and dispersal as antelopes adapted to the many different habitats to be found on the continent, where they found little competition. The native African herbivores of the time included animals like elephants, hyraxes and anthracotheres (early ancestors of hippos). The fast-scampering antelopes with their efficient digestion didn't suffer much from competition with these, and rapidly found numerous niches for themselves. Thus we have today the great variety living everywhere from dense rainforests to vast, open desert plains, in sizes from the tiny Royal Antelope (to be featured here soon) to the massive Eland, and with elaborations to their horns reaching the pinnacle in the spiral-horned Greater Kudu. But with all this evolution going on, the Grysboks remained extremely conservative, remaining on the small side, with very simple horns, and still living in the original forest or thicket environment. This illustrates an important principle of evolution: a 'winning design' doesn't need to be changed. In many groups you find the same thing: while some kinds change and diversify rapidly and massively, others hardly change at all, even over very long periods. They've hit on a winning formula early on. Their shape and way of life is simply so well-suited to their environment, that additional change is not only unnecessary, but undesirable – only likely to make them worse at their particular way-of-life in their environment. So, as long as that kind of environment exists, their design is likely to persist.
The way of life of the Grysbok is not a very social affair. Rams and ewes pair up and remain in small territories. They browse on a variety of trees, shrubs and herbs, and will eat fruits and flowers also. They're able to extract as much moisture as they need from this herbage, and don't need open water to drink from. They use scent as the main way to mark out their territories. They have large scent glands at the corners of their eyes, exuding a sticky, black stuff, which they rub onto twigs or glass stalks. The male also marks his territory with urine and dung deposited on middens. If he encounters another male invading his territory, and is unable to scare him off by aggressive posturing and fluffing up his rump fur to make himself look bigger, they will fight, using their small horns to potentially deadly effect.
The shrubland habitat of the grysboks stretch from the winter rainfall region in the west, to the summer rainfall region in the east. Indeed, where they occur, they can breed at any time of the year, and in a good year a ewe can even give birth twice. Only a single lamb is born at a time; it is a very cute little thing with a short snub-nose. Its fur is dense and somewhat darker than that of the adult. The lamb keeps itself well-hidden while the mother goes off to feed; she returns to clean and suckle it each day.
Grysboks, being small and not very well defended, can fall prey to a variety of predators such as leopards or caracals, with the young lambs also being vulnerable to large eagles. They are hunted by people, but not particularly heavily. They're sometimes persecuted for destroying grapevines or other crop plants. Even so, they're still quite numerous over most of their range. But because of this range being rather small, and vulnerable to deterioration as a result of human activities (such as conversion to farmland or plantation, or invasion by alien plant species) they should be watched carefully for declines. We still know far too little about this charming and versatile little antelope.
