FEEDING 



263 



Pigmy Right Whale is black at the outer and cream on the inner side. 

 The average number of plates on either side of the mouth of Biscayan 

 and Pigmy Right Whales is 230, and that of Gi'eenland Whales about 300. 



Californian Grey Whales and all Rorquals have very much shorter 

 plates (Fig. 138), i.e. Blue Whale, 3^ feet; Humpback, 2|^feet; Fin Whale, 

 24 feet; Sei Whale, 2 feet; Californian Grey Whale and Bryde's Whale, 

 i;j feet; and Little Piked Whale, 8 inches. Because of the shorter plates, 

 the rostra of these animals are not arched, nor do they have the specially 

 large lower lip of Right Whales, though the Grey Whale's rostrum is 

 somewhat curved at the top. The Blue Whale has 250-400, the Sei Whale 

 an average of 330, Bryde's Whale 270, the Humpback Whale 300-350, 

 and the Little Piked Whale 300 baleen plates on either side of the mouth. 

 Blue Whales, Sei Whales and Humpback Whales have black plates. Fin 

 Whales have black, blue and cream plates, Bryde's Whales have white and 

 black plates, and the baleen of Little Piked Whales is cream-coloured 

 throughout. The hairy fringe is usually of the same colour as the horny 

 plates, but in Sei Whales it is white, and, moreover, so soft and fine that 

 it looks like wool. This explains their diet of very small food, just as the 

 stiffer structure of the Bryde's Whale baleen explains their diet of fish. 

 The plates at the centre of the row are thickest and longest, those at the 

 ends are shorter and narrower, and the extremities of the row consist of 

 separate hairs. 



Baleen is made of the same substance as our own hair and nails or as the 

 horns of cattle. In cross-section, baleen is seen to consist of a homogeneous 

 cortical layer enclosing three to four layers of horny tubes (Fig. 141) which 

 become progressively thinner towards the centre. Knowledgeable readers 

 will appreciate that, from a structural point of view, baleen therefore 

 resembles normal bone or the 'unbreakable' front forks of some bicycles 

 which also consist of a homogeneous outer layer and a number of internal 

 tubes, this construction combining minimum weight with maximum 



Figure 141. Cross-section through the baleen of a Fin 

 Whale showing its construction from horny tubes enclosed 

 by cortical layers. {Ruud, 1940.) 



