298 THE WEALTH OF THE SEA 



They are so large that twins wre seldom born. 

 Mother whales nurse their young at sea, but few 

 persons have ever seen this interesting sight. 



There are more than thirty known species of 

 whales, not counting the many related species of 

 sea mammals such as porpoises and dolphins, but 

 only seven species are of commercial importance. 

 The sperm-whale, the North Atlantic right whale, 

 and the bow-head or Greenland right whale have long 

 been considered the most important. But since, whale 

 meal and other products have become of consider- 

 able value, the humpback, the sulphur-bottom or 

 blue whale, the sei whale, and the finback have come 

 to possess great value. 



Of these the sulphur-bottom or blue whale is the 

 largest. Indeed this whale is not only the largest 

 animal that lives to-day, but is also the largest 

 animal that ever lived. Contrary to the general be- 

 lief, the gigantic lizards called dinosaurs, which 

 formerly inhabited the swamps and rivers of the 

 western part of North America, were neither so long 

 nor so heavy as the blue whale. The largest authen- 

 tic specimen of blue whale that has been measured 

 was eighty-seven feet in length and weighed about 

 seventy-five tons. This whale is found in almost all 

 seas, and is now captured in larger numbers than 

 any other whale. About two thousand of these 

 whales are taken each year in the vicinity of the 

 Falkland Islands. The blue whale belongs to the 

 whalebone class, but the whalebone taken from its 

 jaw is short and of little value. 



