PARTS OF ANIMALS, IV. x. 



the only animal that stands upright. Hence, Nature, 

 so as to make the upper parts light and easy to carry, 

 took off the corporeal matter from the top and trans- 

 ferred the weight down below ; and that is how she 

 came to make the buttocks and the thighs and the 

 calves of the legs fleshy. At the same time, in 

 making the buttocks fleshy, Nature made them useful 

 for resting the body. Quadrupeds find it no trouble 

 to remain standing, and do not get tired if they 

 remain continually on their feet — the time is as good 

 as spent lying down, because they have four supports 

 underneath them. But human beings cannot remain 

 standing upright continually with ease ; the body 

 needs rest ; it must be seated. That, then, is why 

 man has buttocks and fleshy legs, and for the same 

 reason he has no tail : the nourishment gets used up 

 for the benefit of the buttocks and legs before it can 

 get as far as the place for the tail. Besides, the 

 possession of buttocks takes away the need and 

 necessity of a tail. But in quadrupeds and other 

 animals it is the opposite : they are dwarf-like, which 

 means that their heavy corporeal substance is in the 

 upper part of them and does not come into the lower 

 parts ; and as a result they have no buttocks and their 

 legs are hard. Yet to ensure that the part which 

 serves them for the discharge of the residue shall be 

 guarded and covered over, Nature has assigned to 

 them tails or scuts by taking off somewhat of the 

 nourishment which would otherwise go into the legs. 



(The Ape is, in form, intermediate between the 

 two, man and quadruped, and belongs to neither, or 

 to both, and consequently he has no tail, qua biped, 

 and no buttocks, qua quadruped.) 



There are numerous differences in the various tails, 



n2 387 



