Natural History 373 



feet are equal in length, but the front feet are broader. 

 This is the rule among true quadrupeds. The series of 

 tracks — that is, its traU — shows the manner of the cat 

 in walking. In this the animal used apparently but two 

 legs, because the hind foot falls exactly on the trail made 

 by the front foot, each track being really doubled. This 

 is perfect tracking. There are several advantages in it. 

 Every teamster knows that a wagon whose hind wheels 

 do not exactly follow the front wheels is a very bad wagon 

 to haul in sand, snow, or mud. The trail for it has to be 

 broken twice, and the labor increased, some say, 50 

 per cent. This same principle holds good in the case of 

 the cat track: by correct following the animal moves more 

 easily. But there is still a more important reason. A 

 hunting cat sneaking through the woods after prey must 

 keep its eyes on the woods ahead or on the prey itself. 

 At the very most it may pick out a smooth, safe, silent 

 place for its front feet to tread on. Especially at the 

 climax of the hunt all its senses are focussed on the intended 

 victim; it cannot select a safe spot for each hind foot 

 in turn, even though the faintest crunch of a dry leaf 

 will surely spoil the stalk. But there is no danger of that; 

 the cat can see the spots selected for the front feet, and the 

 hind feet are so perfectly trained that they seek unerringly 

 the very same spots — the safe places that the front 

 feet have just left. Thus perfect stepping is silent stepping, 

 and is essential to all creatures that stalk their prey. 

 The opposite kind of stepping is seen in very heavy animals 

 which frequent marshy ground; to them it would be a 

 positive disadvantage to set the hind foot in the tread 

 of the front foot, where so much of the support has just 

 been destroyed. The ox illustrates this. These principles 

 are applicable in geology, where the trails are the only 

 biographical records of certain species. From the manner 



