142 



M A M M A L I A. 



are several others which use the claws chiefly in 

 ascent, such for instance as the climbing cats, and 

 some other tree animals, the greater part of which 

 are inhabitants of India. The squirrel tribe have a 

 compound mode of climbing; they ascend the thick 

 trunks of trees by the help of the claws, by leaping, 

 and by supporting themselves with their flying mem- 

 branes, and their very much produced tails, which act 

 as parachutes, as the peculiar character of their fur 

 takes a considerable hold on the air. They thus 

 leap among the small branches, more after the manner 

 of birds than of common mammalia, though none of 

 them can take a fresh impulse from the air itself. 

 Among the flexible branches and twigs of a tree, a 

 squirrel, however, derives an advantage in leaping, 

 something similar to that which a stage tumbler de- 

 rives from his elastic boards. The animal alights on 

 the flexible branch or twig from a considerable dis- 

 tance, and with a good deal of impetus, so that the 

 force with which it bends the branch is much greater 

 than could be given by the pressure of its weight. 

 This force is impulsive, and therefore its effect lasts 

 only for a moment, and when it is over the twig 

 recoils against the mere weight of the animal, and 

 assists in giving it impetus for a fresh spring. The 

 rapid march of the squirrel along the tops of the trees 

 is therefore not nearly so fatiguing as might be ima- 

 gined by those who do not reflect upon the assistance 

 which it gets from the elasticity of the tree. In 

 ascending or descending from near the extremity of 

 one branch to near that of another, these animals, and 

 indeed all animals which ascend or descend by these, 

 derive similar advantages, though the mode in which 

 they derive it is not exactly the same in the ascent 

 and the descent. When the animal ascends and 

 catches an elastic branch, whether it catch it with a 

 grasping hand or by any other means, the recoil of 

 the branch throws it upward, so that it can reach a 

 higher one at the next spring than it could do if it 

 started from a nonelastic support ; and thus it proceeds 

 until it gains the elevation at which it either finds its 

 food, or gets beyond the reach of its enemies. In 

 descending the recoil of the branch tends to throw 

 the animal upward, and this enables it to descend 

 upon the next branch with more velocity, and by this 

 means leaves it with more command of its grasping 

 organs. In fact, the elasticity of the branch adds 

 very much in the way of a parachute in breaking the 

 fall of the animal, so that an animal incapable of 

 grasping while it descends, falls through the elastic 

 twigs of a tree from a considerable height with much 

 less injury than if it fell through a half, or even a 

 third, of the same height without any elastic inter- 

 ruption. Every twig or yielding branch that it 

 touches, takes off a considerable portion of the velo- 

 city which it has acquired during the previous fall ; 

 and it would not be difficult to suppose branches so 

 tangled and so elastic, that a man might tumble 

 through twenty thirty, or forty feet of them, and reach 

 the ground without any material injury. 



Among all this variety of mammalia which ascend 

 and descend on trees, besides several others which 

 climb rocks and other steep surfaces, solely by bound- 

 ing in some cases, and partially by the claws in others, 

 the true climbers ate those which are capable of com- 

 paratively little motion upon the ground, and are 

 very seldom found upon it, except when they have 

 to make their comparatively slow and ungainly jour- 

 neys from tree to tree, or from the trees to the water. 



There is, however, a gradual change of character in 

 the climbing organs, even in the quadrumana, until 

 they ultimately terminate in what may be termed simple 

 hooks rather than hands, having the fingers, or strictly 

 speaking the toes, furnished with long sharp and bent 

 claws, so that they climb either by bending the toes 

 across a branch, or make their way longitudinally 

 clinging by means of the claws and the spread of the 

 toes. Animals which have this structure are all 

 nocturnal, living in obscurity in the depths of the 

 forests, and feeders upon insects, small birds, and very 

 small mammalia, upon which they steal in the dark ; 

 and therefore we are but little acquainted with their 

 habits in a state of nature, and capable of judging 

 only very imperfect!}' of the manner in which they 

 use their feet in climbing. 



Perhaps the most typical of the climbing animals, 

 which climb by means of hands, or more correctly, 

 grasping feet, for there is really no true hand in the 

 whole range of animated nature except the hand of 

 man, are the apes properly so called, namely the 

 tailless ones, which have no appendage to the sacral 

 extremity of the vertebral column, either as a balance 

 in their motions, or as an additional grasping instru- 

 ment. 



Attempts have often been made to institute a 

 parallel between those animals, more especially the 

 chimpansee and the human subject ; and it has been 

 supposed that this parallel extended even to the 

 length of intellectual sagacity. This last, however, 

 is completely without foundation, and even the mere 

 animal motions differ in kind and not in degree. In 

 the fore foot of the chimpansee, and of all those apes 

 which take their food with the paw, and prepare it if 

 necessary by means of the two paws ; the paw has a 

 double function to perform, being equally a climbing 

 instrument, and a prehensile one in the article of their 

 food, and along with the mere prehension, it can break 

 that food or otherwise prepare it, which may be consi- 

 dered as an inferior kind of working, though it is really 

 a part, and a necessary part, of the act of prehension ; 

 in proof of which we find it exercised to a very consider- 

 able extent by some of the clutching and the climbing 

 birds. In addition to these, its double functions, 

 when the ape is in the tree, the fore leg has a third 

 function to perform, in the exercise of w hich the great 

 development of the paws, and their pliable structure, 

 are disadvantageous to it. This is the act of walking, 

 when the animal finds it necessary to be on the 

 ground. 



The three functions are perhaps more complete in 

 the chimpansee than in any other of the apes, and 

 therefore its fore paws can be applied to a greater 

 number of purposes. These purposes may, however, 

 be, generally speaking, reduced to modifications of 

 three taking food, climbing, and doing mischief, that 

 is tearing things to pieces. An animal of this kind 

 may be taught to sit at table, to use a knife and fork, 

 or to drink out of a glass, which latter operation is 

 sketched in the figure on the following page. 



In all these, however, and in every action which 

 such an animal can be made to perform, there is not 

 the slightest resemblance to the action of the human 

 hands, any farther than that there is a mere grasping. 

 That grasping is performed chiefly by the long fingers, 

 to which the thumb acts merely as a point of resist- 

 ance, and no way directs the general motion of the 

 paw, whereas in the human subject, though the thumb 

 contains a joint fewer than the fingers, its revolving 



