African Nature Notes and Reminiscences

by Frederick Courteney Selous

I imagine that the white-faced bontebok was evolved from the same ancestral form as the topi and the tiang of East and Northern Africa, for the new-born bontebok as well as the blesbok has a blackish brown face, and I believe—however fantastic this belief may appear to be—that the wonderfully rich and varied coloration of this remarkable antelope has been brought about purely through the influence of its exceptional environment. The plains where these animals live lie along the shore of a deep blue sea, the ground beneath their feet is at certain seasons of the year carpeted with wild flowers, which grow in such profusion that they give a distinct colour to the landscape, whilst above them rises a range of mountains of a considerable altitude, the upper parts of which are often covered with a mantle of pure white snow. I cannot imagine how any one who has seen bonteboks on the plains they inhabit can believe that their white rumps, faces, bellies, and legs, contrasting as they do so vividly with the dark rich brown of their sides and necks, can afford them any protection against their carnivorous foes; nor, although a white rump or face is a conspicuous mark, can I see the necessity of recognition marks for animals which live on open plains where the vegetation is short, and where an animal's whole body can be seen at a long distance.

In the blesbok, which also lives on open plains, the white rump patch so conspicuous in the bontebok has become pale brown, as, I think, through the influence of the dull monotonous colours of the dreary, dull-coloured country in which it lives. Ages ago no doubt the bontebok spread northwards through the karroo into the countries beyond the Orange and the Vaal rivers, but the gradual desiccation of the whole of South-Western Africa, which has been going on for a very long time, must have gradually driven all the bonteboks outside the Cape peninsula northwards to the Orange river, and completely separated them from their relatives still living near Cape Agulhas. These latter have retained all their richness of coloration brought about by the influence of their very striking surroundings, the deep blue of the sea, the snow on the mountains, and the bloom of innumerable wild flowers. The northern herds moved into open plains, in themselves very similar to the plains near Cape Agulhas, but they are never carpeted with wild flowers, nor are they skirted by a deep blue sea, nor ever overlooked by snow-covered mountains. Is it not possible that the differences which exist to-day between the coloration of the bontebok and the blesbok are entirely the result of the absence of any kind of colour but various monotonous shades of brown in the countries in which the latter species has now been living for a long period of time?

Not only has the rich and beautifully variegated body colouring of the bontebok become an almost uniform dark brown in the blesbok, but the snow-white disc on the rump of the former animal has turned to a pale brown in the latter, whilst the area of white on the face and legs of the bontebok has already been considerably contracted in the blesbok.

Personally, I look upon the blesbok as a faded bontebok; faded because it moved northwards out of the richly coloured environment in which it was first evolved into the dull-coloured plains of its present habitat, where it subsequently became isolated owing to the desiccation of the intervening country.

Could the opening up of Africa by the destructive civilised races have been delayed for a few hundred or a few thousand years, the blesbok would no doubt have lost the white blaze down the face as completely as it has lost the white disc over the tail, which is so conspicuous a feature in the coloration of its immediate ancestor, the bontebok. To those who believe that every spot or stripe or patch of colour on every animal is a beautiful illustration of the truth of the theory of protective coloration, this may seem a very fanciful idea. Yet I feel convinced that the influence of environment has played a greater part than is generally believed in the evolution of colour in living organisms. The weak point in the theory of protective coloration when applied to large mammals is the fact that all carnivorous animals are nocturnal and seek their prey habitually by night and by scent, and only occasionally by daylight and by sight.

I submit that the beautiful case in the Central Hall of the Natural History Museum at South Kensington—showing an Arctic fox, in its white winter coat, approaching a Polar hare, also in winter dress, and an ermine (stoat) hunting for ptarmigan (evidently by sight)—gives an entirely false view of the struggle for life as carried on by animals inhabiting the Arctic Regions, for it conveys the idea of the carnivorous animals of those snow-covered wastes hunting for their prey in a bright light and by eyesight alone.

But the truth is that the Arctic winter, during the long continuance of which all living resident creatures, with the exception of the musk ox, become white,[3] is one long night, in the gloom of which the wolves and the foxes and the ermines (stoats) search for and find their prey by scent alone, just as foxes, stoats, and weasels do in this country. As long as a hare gives out any scent at all, a fox will be able to follow and find it. The fact that the hare has turned white in the snow-covered ground in which it is living will not help it as long as it throws out the scent of its species, nor can it be shown that the foxes of the sub-Arctic regions, which never turn white in winter, have any greater difficulty in approaching and killing the white hares on which they live than the white Arctic foxes experience in catching the Polar hares.

[3] I do not admit that the raven is a truly Arctic bird. Nansen, in Farthest North, although he kept careful records of all the birds seen during the three years his expedition lasted, never mentions having seen a raven, which I believe has only penetrated into the Arctic Regions, as an excursionist, in comparatively recent times, following the whaling ships, and living on the carcases of the whales and seals killed.

There is one other point regarding the protection afforded by colour to large mammals against carnivorous foes which I think has not been sufficiently considered by naturalists, and that is, that no matter how well the colour of an animal may harmonise with its surroundings as long as it remains perfectly still, as soon as it moves "it jumps to the eyes," as the French say, no matter what its colour may be. What is called protective coloration to be effective must be motionless. Movement, even very slight movement, at once destroys its efficacy. But no herbivorous animals can remain constantly motionless. They lie down and rest certainly during the heat of the day, which is, however, just the time when all carnivorous animals are sleeping. At night and in the early mornings and late evenings they move about feeding, and it is at such times that carnivorous animals hunt for their prey. In the dark these latter are undoubtedly guided by scent and not by sight, and I cannot see that it matters much to them whether the beasts on which they prey are black or red or grey or spotted or striped; whilst, if they should happen to be still hunting after daylight, any antelopes or other animals feeding and moving about within their range of vision would at once be seen whatever their colour might be. Every old hunter knows how easy it is to overlook any animal, no matter what its colour or surroundings, as long as it is motionless, and how easy it is to see it as soon as ever it moves.

I have never yet heard any explanation given of the black, and therefore most conspicuous, coloration of the Cape buffalo. If any animals needed protective coloration buffaloes certainly did, for in the interior of South Africa they formed the favourite food of the lion, and enormous numbers of them must have been annually killed by these powerful carnivora, which seemed to live with and follow the larger herds in all their wanderings.