2(>n WHALES AND DOLPHINS 



coupled with rapidity of movement. The head passes back- 

 wards without break of an}' sort into the beautiful streamlining 

 of the body. The flippers are rounded in outline and do not 

 taper to a point as in most typical dolphins ; the back fin is a 

 conspicuous feature situated about midway along the dorsal 

 surface of the body. The flippers, dorsal fin and tail flukes 

 are remarkable in this species for the great disproportionate 

 increase in size which takes place in old males. In young 

 animals of both sexes, and in the female irrespective of age, 

 the flipper length is about one-ninth of the total body length. 

 In the old male animal the flipper has grown enormously, so 

 that it is one-fifth of the entire length. A cast of a flipper 

 from a 30-foot animal exhibited in the British Museum (Natural 

 History) is equivalent in size to that of a Right Whale more 

 than double the Killer's length. Coinciding, with the enlarge- 

 ment of the flipper the dorsal fin, from being recurved and a 

 foot or two in height, lengthens to about 6 feet, and becomes 

 triangular and attenuated in form. This elongation of the 

 dorsal fin gives the Killer the alternative name of " Swordfish " 

 by which it is sometimes popularly known, and it is this which 

 probably accounts for some at least of the description of attacks 

 on the largest of whales by so-called swordfish. It would 

 seem doubtful whether the true Swordfish habitually attacks 

 the great cetaceans ; certainly there is nothing in the form of 

 wounds either recent or healed on the bodies of Rorquals 

 which have been examined that can be definitely attributed 

 to the Swordfish, whereas every person who has had experience 

 of whaling has had abundant evidence of the voracity of the 

 Killer, and of its daring attacks both on living whales and on 

 the carcasses of freshly killed animals being towed to the whal- 

 ing factory. It has been stated by old writers that the Killer 

 Whale uses its dorsal fin as a weapon when attacking the large 

 whales on which it sometimes preys, but little credit can be 

 attached to this story, for the fin is not supported by any 

 bony skeleton, and is so flexible that it has been observed to 

 bend over to one side or the other when projecting out of the 

 water. It can obviously be of little use except as a balancing 

 mechanism to keep the animal upright when it is swimming 

 at great speed through the water. 



The colour of the Killer is well marked and is distinctive for 



