268 



ZOOLOGY. 



log comprises tin- dog, properly so called, tin- 

 fox. All these animals are character! /ed by a 



The genus 



wolf, and the 



peculiar dent it ion, great strength and agility, SCUM- of hearing 

 and smell acute, claws adapted for digging, and they show ;i 

 partiality (some at least) for putrid flesh as food. Their sight 

 is excellent. 



The domestic dog is distinguished from the other species by 

 the curved tail. This animal is born with the eyelids closed, 

 and they open only after ten or twelve days : the female has six 

 or seven at a birth, and sometimes even twelve. The dura- 

 tion of life is from twelve to fourteen years ; they have been 

 known, however, to live to twenty, and their age is determined 

 by their teeth, which in the young are white, pointed, 

 and cutting, but in the aged blunted, dark coloured, and 

 irregular. 



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. 



.^J/AMtifctt ' _, 



Fig. 197. The Otter. 



The dog is the most complete conquest which man has 

 made in respect of any animal. The entire species ha.- he- 

 come domesticated, so that the primitive condition is lost. 

 The wild dogs found in some countries are merely domestic 

 dogs which, being abandoned, have run wild, and recovered 

 some of their primitive savage habits. Some naturalists 

 are disposed to think that originally there may have been 

 several species of the dog, and others imagine the wolf or 

 jackal to be the origin of the domestic dog ; but when aban- 

 doned on desert isles, the dog never assumes the character of 

 either of these animals. The dogs of people but little civili/ed 

 have the ears erect, and hence it has heen supposed that the 

 shepherd's dog, or chien-loup, is the origin of the domestic dog 

 of all varieties. 



The common wolf is readily distinguished from the dog by 





