246 ADAPTATIONS TO NOCTURNAL ACTIVITY 



We do know that the visual acuity of ungulates is far higher than we 

 would expect to find in the average tapetum-bearing nocturnal animal 

 with its rod-rich retina — the average dog-sized carnivore, for example — 

 despite the rather large absolute size of the eyes of foxes, cats, and the 

 like. The old-time Arab horse breeders are said to have invented a game 

 in which the winner was he whose horse recognized him, from upwind, 

 from the greatest distance — showing its recognition by heading straight 

 for its master who stood with the other owners in a great semi-circle at 

 a considerable distance. The champion seems to have been a horse which 

 recognized his master from 500 meters away. And the vision of the horse 

 is superb by night as well as by day. An Arabian fable cited by Rochon- 

 Duvigneaud runs like this : "The Lion and the Horse were arguing as 

 to which had the better vision. The Lion, on a dark night, could see a 

 white pearl in milk — but the Horse could see a black pearl amidst coal. 

 The judges decided in favor of the Horse." 



Another empirical example, which could hardly be improved upon, 

 is that given in the observations made by an old hunter on the prong- 

 horn (Antilocapra americana), and quoted by Seton: "What a live 

 antelope don't see between dawn and dark, isn't visible from his stand- 

 point; and while you're a-gawkin' at him through that 'ere glass to make 

 out whether he's a rock or a goat, he's a-countin' your cartridges and 

 fixin's, and makin' up his mind which way he'll scoot when you dis- 

 appear in the draw for to sneak on 'im — and don't you ferget it." 



