CHORDATA 399 



nearly four hundred kilos. The polar bear is confined to the 

 Arctic zone; its hair is creamy white, the claws black. It may 

 attain a length of two and a half meters or even more ; its food 

 consists chiefly of fishes and seals, and it is the only bear of 

 aquatic habits. 



Related to the bears are several kinds of smaller Carnivora, 

 many of which are of considerable economic importance because 

 of their valuable fur. The otters have webbed feet, adapted to 

 their aquatic habits. The sea otter is found off the coast of 

 Alaska ; it attains a length of a little over a meter, is extremely 

 shy, and is difficult to catch. The true otters are represented by 

 a species in Brazil, another in Mexico, the common American 

 otter, ranging over the whole temperate zone of North America, 

 — it is one of the largest species, — and the common otter of 

 Europe. This last species is sometimes trained to fish, and the 

 practice is common in India and China as well. The skunks 

 are found in North and South America and are most familiar 

 because of the abundant secretion of their anal glands. The 

 common North American species, Mephitis mephitica, can eject 

 this secretion for a distance of two and a half or three meters, 

 and the odor is so penetrating that it may be perceived at a dis- 

 tance of over a kilometer and a half; they are slow-moving 

 animals and partially hibernate. The badger is common in 

 Europe and Asia. The badger of North America is placed 

 in another genus ; it is abundant west of the Mississippi, feeds 

 upon small rodents such as gophers, and has a broad, flat body, 

 about sixty centimeters long. All the badgers are good burrow- 

 ing animals. In connection with the foregoing should be men- 

 tioned the minks, and the several related species of the same 

 genus, such as the ferrets, the weasels, and the stoat, or ermine. 

 The European ferret, or polecat, is found in Asia as well as 

 Europe. In America we have the black-footed ferret, while the 

 true ferret is a native of Africa and is a permanent albino, with 

 white fur and pink eyes ; they are valuable as ratters. There 

 appears to be only a single species of ermine, Putorius enmma. 

 which extends northward as far as any terrestrial mammal ; it 

 is found in Europe and Asia, and in North America as far as our 

 Southern states. In summer its fur is reddish brown in color, 

 in winter a pure white except the black tip of the tail. It kills 



