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in which the authors treat the current ideas widely accepted by 

 naturalists of less experience ; equal philosophy and wealth of 

 wide observation is shown in the following, in which they discuss 

 the gait of heavy ungulate mammals : " It (the Eland) has one 

 characteristic seemingly inconsistent with its great size and lack 

 of speed, and that is its extraordinary power of leaping. When 

 startled, and beginning a run, the huge cows, and even the bulls, 

 bound like Gazelles, leaping clear over one anothers' backs. It 

 is extraordinary to see such bulky, heavy-bodied creatures spring 

 with such Goat-like agility. It would seem that the mechanical 

 reasons which make the trot their natural gait, and make their 

 gallop slower and more tiring than the gallop of the Oryx or 

 Hartebeest, would also limit their jumping powers ; but this is 

 not the case. They are heavier-bodied than Moose or Wapiti, 

 with huge necks and barrels, and pendent dewlaps and wrinkled 

 neck skin, yet, for a few seconds after starting, they make high 

 jumps of a type which Wapiti rarely, and Moose never, attempt. 

 The Wapiti, however, although their normal gait is also the 

 trot, and although heavy Wapiti bulls are speedily exhausted 

 by a hard gallop, at least sometimes run faster than running 

 Black-tailed Deer — we have seen this ourselves — whereas the 

 Eland is at once left behind by frightened Oryx or Hartebeest — 

 as we have, also, ourselves seen. The Moose is even more of 

 a trotter than either Eland or Wapiti. Young Moose will 

 occasionally gallop, not only when frightened but even when 

 at play ; but the old animals practically never break their trot, 

 except that, as we have been informed by entirely trustworthy 

 hunters, when suddenly and greatly startled they may plunge 

 forward for a few rods in a kind of rolling run. We ourselves 

 once saw the tracks where a big (though perhaps not quite full- 

 grown) Moose had thus plunged for a few jumps at a gallop. 

 These very big and heavy species of Antelope and Deer evidently 

 find the trot, and not the gallop, their natural speed gait, 

 whereas the smaller Deer and Antelope find the gallop equally 

 natural — although the Gerenuk trots fast and the Eocky Moun- 

 tain Blacktail proceeds by buck-jumps. The big Zebra trots 

 much more freely than the small Zebra. From these examples 

 it would seem natural to lay down the rule that increase in size 

 and bulk tends to make the trot mechanically preferable to the 



