164 



NATURAL HISTORY. 



The latter, as'we have already seen, culmina/e in one direction that is, they attain the perfection of 

 structure for a predatory life and flesh diet. The members of the Dog family, again, are flesh-eaters, 

 as a rule, but not exclusively. They are well adapted for hunting and catching living prey, but by 

 no means so perfectly as the Cats ; they are, indeed from a carnivorous point of view the inferiors 

 of the Feline group in teeth, in claws, and in muscular strength and agility. 



The Bears, with which we have now to do, depart as widely from the Dogs in one direction as 

 the Cats in the other ; and their distance from the latter family is great indeed. The Cats attain the 

 perfection of quadrupedal form, while few animals are more clumsy and awkward- looking than a 

 Slcth Bear. Cats walk, with an elegant and silent tread, on the very tips of their toes ; Bears 

 shuffle along with a waddling, though often rapid gait, and with the whole sole of both fore and hind 

 feet applied to the ground, or, in other words, are wholly plantigrade. Cats have a clean-cut, rounded 



face, with beautifully chiselled nostrils and thin 

 lips; Bears a long snout, almost like a Pig's. 

 The fur of Cats is usually short and brilliantly 

 coloured; that of Bears long, shaggy, and sombre. 

 Lastly, while the Cats are almost exclusively 

 flesh-eaters, many Bears are strict vegetarians, 

 or at most eat such matters as Ants and honey, 

 and only have recourse to meat when their 

 favourite food cannot be had. 



In coi'respondence with the partly or en- 

 tirely vegetable nature of the Bear's diet, we 

 find a remarkable series of modifications in its 

 teeth. The front teeth, or incisors, are of con- 

 siderable size, and have three points or cusps. 

 The great eye-teeth, or canines, although large 

 and formidable, are decidedly smaller in rela- 

 tion to the rest of the teeth than in either the Dog or Cat group. Following these are three very 

 small teeth, which usually fall out at an early period, and are, therefore, not to be found in most 

 skulls ; these, as well as the next tooth, which is of considerable size, have their places occupied 

 in the young Bear by " milk-molars," and are therefore called premolars. The last premolar in the 

 upper jaw is succeeded by two, that in the lower jaw by three, time grinders or molars ; so that the 

 " dental formula " of the Bear is the same as that of the Dog, namely, incisors, ^ ; canines, 

 {Zj ; premolars, ^ ; molars, |lg. 



But though the number agrees, the form is very different. The incisors and canines, as we have 

 said, exhibit no difference of importance, but the last premolar and all the molars, instead of having 

 the sharp cutting character they have in the Cat, and to 

 a less degree in the Dog, have comparatively flat crowns, 

 raised up into a number of little elevations or tubercles ; 

 even the " carnassial " teeth (last premolar in the upper 

 jaw, and first molar in the lower) have entirely lost 

 their scissor-blade character, and become true grinders. 

 As a corresponding change, the hinge of the lower jaw 

 is no longer so constructed as to be incapable of any but 

 an Tip and down motion ; it can, on the contrary, be 

 worked from side to side, so that the Bear can actually chew his food. The animal derives a 

 double advantage from this : in the first place, the food can be reduced to a pulp, a very necessary 

 thing for such food-materials as roots, which in an entire state would be highly indigestible ; and, in 

 the second place, it is acted upon for a considerable time by the saliva, and thus partially digested in 

 the mouth, for one of the chief properties of saliva is to convert the insoluble, and therefore indigestible, 

 starchy matter, of which a large part of most vegetable substances consists, into soluble, and therefore 

 digestible, sugar. 



It is a remai-kable circumstance that the teeth have the same form in all the Bears : though, 



TEETH OF POLAR BEAR. 



i, incisors ; c, canines ; pm. preraolars (the second and third of which are 

 .bsrnt in both jawsj ; m, molars. 



TEETH OF POLAR BEAR. 



The Incisors and grinding teeth only are shown, the grinding 

 surfaces of the latter being displayed. 



