416 SAVAGE SUDAN 



immobility (aided in certain cases by mimicry), whereby to 

 escape detection by their foes. It is their feebleness that forms 

 their safeguard ; though whether in their eocene intelligence 

 they realise that fact lies beyond my scope. Their rigid 

 immobility points the conclusion, though it falls short of 

 proving it, I am content to leave the question at that and 

 give them the benefit of the doubt. 



Immobility is the essence of the whole question. The giant 

 elk, in his smoke-grey pelt, assimilates so exquisitely with forest- 

 shades beneath the pines, that he may very easily escape detec- 

 tion, though he stand 6 feet high, his position known, and within 

 100 yards of the hunter ; but one flick of a white-fringed ear 

 betrays him. So, as I write this at my window, with eyes 

 glued to the foolscap, the flight of a passing heron, or plover, 

 or gull, the capering of a rabbit 200 yards away across the 

 river, unfailingly attracts attention. 1 Nothing that moves, even 

 though but a part an ear or a tail is protected, be its colour 

 what it may. As a general rule the reverse holds true that a 

 creature, provided it remains stationary, is unlikely to be dis- 

 covered. To this latter, however, there are exceptions. For 

 example, so conspicuous are the white facial adornments of 

 waterbuck, sable and roan antelopes that, even when standing 

 at gaze in absolute quiescence, although concealed among thick 

 covert, these animals will often be detected thereby, despite 

 the otherwise general harmony of their hues with those of the 

 bush around. 



The zebra has customarily been selected as an illuminative 

 example of the principle of colour-protection. Precisely why, it 

 is difficult to understand, since scarce an animal on earth is more 

 conspicuously coloured a "thunder and lightning " pattern, to 

 borrow Dr Drummond's description. Possibly the selection 

 lent occasion for a sort of gladiatorial display in dialectics ; since 

 there are controversialists who revel in Herculean feats, such 

 as squaring the circle or demolishing (on paper) the granite 

 rocks. 



Their contention is that beyond a certain distance say 



1 It may be of interest to mention that during upwards of a score of 

 years, I have kept systematic notes of the birds identified from the said 

 window. It overlooks North Tyne and a wide sweep of country moor, 

 wood, and water. At present the list exceeds ONE HUNDRED species. 



