ECONOMIC ZOOLOGY. 



399 



are known as furs. Most of these, as the seals, the sable, 

 mink, ermine, weasel, raccoon, foxes, skunk, members 

 of the cat family, and some others, belong to the carnivora. 

 A few, as the squirrel, the hare, and the beavers (now 

 almost extinct) are from the rodents. 



One of the most marvelously delicate and beautiful of 

 our fabrics, silk, is a secretion spun out by the larvae of 

 the silk-moth in making the cocoon in which it pupates, 

 or changes to the adult stage. It is killed by being put 

 into hot water, and then the silk thread is unwound. 

 The silk industry is of much importance in China, Japan, 

 Italy, and France. 



399. Animals Used in Saving Human Labor. In the 



earlier stages of civilization this help consisted of aid in 

 hunting and capture of food-animals. The dog was 

 probably one of the first animals domesticated. Later 

 others came to be used for riding, for drawing loads 

 in vehicles or otherwise, for plowing the soil, and the like. 

 The camel, the ox, the horse, and the elephant rank 

 among the most valuable in this respect. In the earlier 

 civilizations of the orient, the camel has been of the 

 utmost value. His adjustment to the tropical and semi- 

 arid conditions is striking. The "ship of the desert" 

 is an older means of commerce than the navigation of 

 the sea. His relatives in South America, the llamas, 

 have long been used as the chief animal of burden in the 

 Andes. The reindeer is at once camel, horse, and ox of 

 the frigid zone. The dog is also a beast of burden over 

 the snows. 



In modern times the horse has come to be one of the 

 most valuable of animals used by man, ranking in money 

 value next to the cattle in the United States. The mule, 



