African Nature Notes and Reminiscences. Frederick Courteney Selous
upon thousands of Burchell's zebras. Should these animals be approached when standing amongst trees with the leaf on, they are not at all easy to see, and the whisking of their tails will probably be the first thing to catch one's eye; but in open ground, and that is where they are usually met with, no animals could be more conspicuous. I have seen zebras too by moonlight, but that was many years ago, and I did not then take any special note of their appearance; but my impression is that they were no more invisible than other animals, but looked whitish in colour when the moon was shining on them, and very dark when it was behind them. As, however, zebras have a very strong smell, and lions usually hunt them by scent and at night, I cannot think that their coloration, whether it be conspicuous or not, matters very much to them, though I look upon the theory that the brilliantly striped coats of these animals render them in reality inconspicuous as absolutely untenable, as it is not in accordance with fact.
When in East Africa I came to the conclusion that not only the zebras, but also the impala antelopes—which are of a much richer and darker red than in South Africa—were conspicuously coloured, and therefore very easy to see; whilst the broad black lateral band dividing the snow-white belly from the fawn-coloured side in Thomson's gazelles showed these little animals up with the most startling distinctness on the bare open plains they inhabit.
To my eyes, and in the bright sunlight of Africa, the juxtaposition of black and white markings, so often seen on the faces of African antelopes, has never seemed to produce an indistinct blur of colour except at a considerable distance. At any distance up to 300 yards the black and white face-markings of the gemsbuck, the roan, and the sable antelope always appeared to me to be distinctly visible, and they have often been the first parts of these animals to catch my eye.
It is all very well to say that a male sable antelope, in spite of its bold colouring, is often very difficult to see. That is no doubt the case, but that only means that there is no colour in nature, and no possible combination of colours, which at a certain distance, if stationary, would not be found to harmonise well with some portions of, or objects in, an African landscape. Speaking generally, however, the coloration of a sable antelope bull makes him a very conspicuous object to a trained human eye, and also, one would suppose, to that of a carnivorous animal, were it watching for prey by daylight.
CHAPTER II
FURTHER NOTES ON THE QUESTIONS OF PROTECTIVE COLORATION, RECOGNITION MARKS, AND THE INFLUENCE OF ENVIRONMENT ON LIVING ORGANISMS
Occasional resemblance of African mammals to natural objects—Hartebeests—Elephants—Giraffes—Coloration of the Somali giraffe—Giraffes not in need of a protective coloration—Koodoos and sable antelopes—Acute sense of hearing in the moose—Possible explanation of large size of ears in the African tragelaphine antelopes—Coloration of bushbucks, situtungas, and inyalas—Leopards the only enemies of the smaller bush-haunting antelopes—Recognition marks—Must render animals conspicuous to friend and foe alike—Ranges of allied species of antelopes seldom overlap—Hybridisation sometimes takes place—Wonderful coloration of the bontebok—Coloration distinctly conspicuous and therefore not protective—Recognition marks unnecessary—Coloration of the blesbok—The blesbok merely a duller coloured bontebok—Difference in the habitat of the two species—The coloration of both species may be due to the influence of their respective environments—The weak point in the theory of protective coloration when applied to large mammals—Hares and foxes in the Arctic and sub-Arctic Regions—The efficacy of colour protection at once destroyed by movement—Buffaloes and lions—General conclusions regarding the theory of protective coloration as applied to large mammals.
Certain observations have been made and theories propounded on the occasional resemblance of African mammals to natural objects, which have never seemed to me to have much significance, although they are often referred to as valuable observations by writers on natural history.
Thus it has been said that hartebeests, which are red in colour, derive protection from their enemies owing to their resemblance not only in colour but also in shape to ant-heaps, and that giraffes gain an advantage in the struggle for life owing to the fact that their long necks look like tree-trunks and their heads and horns like broken branches.
Well, hartebeests are red in colour wherever they are found all over Africa. Ant-heaps are only red when they are built of red soil. In parts of the Bechwanaland Protectorate, where the Cape hartebeest used to be common, the ant-heaps are a glaring white. In East Africa, in different portions of which territory hartebeests of three species are very numerous, all of which are bright red in colour, red ant-heaps are certainly not a conspicuous feature in all parts of the country, and there were, if my memory serves me, very few ant-heaps of any size on the plains where I met with either Coke's, Neumann's, or Jackson's hartebeests.[2] But even in those districts where the ant-heaps are red in colour, and neither very much larger nor smaller than hartebeests, they are usually of one even rounded shape, and it would only be here and there, where two had been thrown up together forming a double-humped structure, that anything resembling one of these animals could be seen. Such unusual natural objects must be anything but common, and cannot, I believe, have had any effect in determining the bodily shape of hartebeests, though, if the coloration of animals is influenced by their environment, red soil and red ant-heaps may have had their influence on the colour of the ancestral form from which all the various but nearly allied species of hartebeests have been derived.
[2] The plains along the railway line between Simba and Nairobi, the open country between Lakes Nakuru and Elmenteita, or the neighbourhood of the road between Landiani and Ravine Station.
I was once hunting in 1885 with a Boer friend (Cornelis van Rooyen) near the Umfuli river in Mashunaland. We were riding slowly along, followed by some Kafirs, and driving a donkey carrying corn for the horses in front of us, when we saw what we took to be some boulders of black rock in the open forest ahead, but some distance away, as we were crossing an open valley at the time. In this particular part of the country great boulders of black rock were a common feature in the landscape. Suddenly our donkey pricked his ears, and stretching out his nose, commenced to bray loudly. Immediately one of the black rocks, as we had thought them to be, moved, and we soon saw that what we had taken for rocks were elephants. Our donkey had smelt them before either my friend or myself or any of our Kafirs had been able to distinguish what they were. As, however, elephants are only occasionally encountered in forests through which great boulders of black rock are scattered, I do not believe that these huge quadrupeds have been moulded to the shape of rocks by the need of a protective resemblance to inanimate objects, any more than I think that the abnormal shape of certain ant-heaps has had anything to do with the production of the high wither and drooping hind-quarters of the hartebeest.
As to the theory that the long neck and the peculiarly formed head of the giraffe have been evolved in order to protect this remarkable animal against its carnivorous foes, by giving it the appearance of a dead or decayed tree, I personally consider such an idea to be so fantastic and extravagant as to be unworthy of serious consideration.
In the course of my own hunting experience, I have shot a great many giraffes to obtain a supply of food for my native followers, and under the guidance of Bushmen have followed on the tracks of many herds of these animals until I at length sighted them. In certain parts of the country frequented by giraffes in Southern Africa, large camel-thorn trees (Acacia giraffae) grow either singly or a few together amongst a wide expanse of wait-a-bit thorn scrub, which is from 6 to 12 feet high. From time to time these large trees die and decay, until nothing is left but a tall straight stem, standing up like a telegraph pole (only a good deal thicker) amongst the surrounding scrub. When, whilst following on giraffe spoor through such country, something suddenly comes in view protruding from the bush, perhaps a mile ahead, the Bushmen will stop and take a good look at it. Of course at a very great distance it is impossible for even a Bushman to distinguish between the tall straight stem of a dead tree