316 UNDERWATER GUIDE TO MARINE LIFE 



animals possess no sense of smell and probably hunt their fish or plankton prey 

 chiefly by sight or taste. Their intelligence is high as a group, that of the bottle- 

 nosed dolphin being comparable to that of a dog. 



Whales have been much reduced by whaling. Supposedly, international law 

 regulates the yearly catch, but this law unfortunately shows few signs of 

 restoring former whaling grounds. Most of the smaller dolphin species are rare 

 and if seen, especially if they are stranded on beaches, should be reported to 

 the nearest scientific institution. 



The habits of most of these animals are very poorly known. Good accounts 

 of many of them are found in Norman and Eraser (1938). Their distribution 

 is world-wide in all seas. The larger ones are more typical of cold waters where 

 the plankton is concentrated. 



Whalebone or Baleen Whales: Suborder Mysticeti 



These are the most gigantic of all living things and, indeed, the largest 

 animals that have ever lived. The suborder name refers to the fact that they 

 have no teeth. Instead, baleen or whalebone, a horny epidermal derivative, hangs 

 down in plates from the palate. This is used to strain plankton from sea water. 

 A huge mouthful of water and plankton is taken into the mouth. The tongue 

 presses up against the baleen plates and expels the water through the screen of 

 baleen which holds the plankton. Then the plankton is swallowed. Such huge 

 animals, it might be supposed, could not possibly find enough plankton to eat, 

 but marine crustaceans, especially krill (euphausians) and copepods, become 

 amazingly plentiful in summer in cold seas. So thick does the water become 

 with them that powerful ships are slowed to half their speed when traveling 

 through such water. The baleen whale's spout, which is thrown vertically 

 upward, is double because of the paired blowhole. 



BLUE WHALE (SLILPHUR-BOTTOM WHALE, RORQUAl) : 



Balaenoftera musculus 



Size: This is the largest animal that has ever lived. Averages 60 to 80 feet long. 

 Up to 103 feet. 



Weight: At 76 feet it weighs 63 tons. At 89 feet it weighs 119 tons. 



Distribution: All seas, but particularly arctic and antarctic waters. 



Identification: The throat and chest have a series of longitudinal pleats. The 

 body is slender and tapering for a whale, and the top of the head flattened 

 and broad. 



Habits: These are perhaps the swiftest of large baleen whales, said to be able 

 to attain 12 miles per hour. The young are 24 feet long when born and take 

 one year in gestation. This embryonic growth rate is astonishingly fast and 

 probably represents a record for any type of growth rate. These are not 

 aggressive animals and are probably quite timid. Their only enemies are parasites, 

 the killer whale, and man. The most destructive of these is man, but the most 

 fearful, to the human eye at least, is the killer whale. 



Similar Species: The other common rorqual or ridge-throated whale is the 

 65-foot finback, Balaenoptera physaJiis, which has small flippers, a ridged back. 



