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.