4 A BOOK OP WHALES 



Not so intelligible as the last reason for enormous 

 growth in size, but apparently to be proved by 

 statistics, is the inference that large size is in pro- 

 portion to the degree of organisation of the creature. 

 The simplest of all living creatures, the Protozoa, 

 are at the same time the smallest. Vertebrates grow 

 to a larger size than Invertebrates, and finally 

 Mammals, as represented by whales, grow to be the 

 giants of the animal creation. 



Another favouring circumstance to large increase 

 in size is abundance, and easiness of capture, of food, 

 as well as freedom from foes. 



The tiger or lion, at the expense of great expendi- 

 ture of force, hunts down an antelope or a deer, while 

 the whale gulps in huge mouthfuls of "whale food' 

 with ease and comfort. Protected by its thick 

 covering of fat, it does not readily fall a victim to 

 any foes ; indeed, the only powerful enemy that it 

 has at all is the Killer whale, Orca, and it is not 

 always that a Greenland whale succumbs to a shoal 

 of those marine tigers. An ingenious suggestion 

 has been made, which covers some of the apparent 

 exaggerations in the dimensions of whales attributed 

 to the ancients. M. Pouchet * thinks that, since 

 in old times whales were not hunted, at any rate 

 to the extent that they are now and have been 

 lately, they may possibly have had the opportunity 

 of growing to larger dimensions. The sailor, 

 Nearchus, is quoted by M. Pouchet upon the size 

 of a Megaptera of the Persian Gulf perhaps the 



* Comptes rendus Soc. Biol., 1890, p. 686, and 1892, p. 422. 



