WHALES, SEALS AND WALRUSES 



and Steered it into a holding tank, in which they were all 

 brought ashore and put into the aquarium. 



Four of the sharks died shortly after. They had not 

 been injured in any way. Siebenaler said, ''They died of 

 fright — or maybe from the emotional shock of being 

 touched by a human being." Mr. and Mrs. Siebenaler 

 spent the whole of one night "walking" the fifth shark — 

 going to and fro with him the whole length of the tank, 

 caressing him and trying to coax him out of his state of 

 nervous shock. But they could not overcome his fear with 

 all their kindness — like the other four he died of fright. 



Siebenaler declared that it was the usual story of 

 sharks in aquariums. Other fish settle down and get 

 used to their keepers and their surroundings. Sharks 

 never lose their fear of human beings and few last longer 

 in aquariums than several weeks. 



Whales — and the term includes dolphins and por- 

 poises — belong to the order Cetacea. Dolphins and 

 porpoises (including the narwhal with its curious single 

 tusk) have been described in an earlier chapter, among 

 creatures which leap from the sea's surface. There are 

 three sub-orders of the Cetacea : Mjstacoceti, including 

 all those whales whose teeth are rudimentary and useless 

 and are replaced by whalebone, or baleen; Odontoceti, 

 which includes all whales having teeth — sperm whales, 

 killer whales, porpoises and dolphins ; and Archaeceti, the 

 extinct whales. Dismissing the third class as of little 

 interest to us in this chapter, we confine our survey to the 

 typical whales of the first two sub-orders, the baleen or 

 toothless whales, and the toothed ones. 



Whalebone is the material in a whale's jaws which 

 enables it to strain its food. It is formed as a development 

 of the ridges, often horny in character, which are found 

 on the roof of the mouth in all mammals. It takes the 

 form of triangular plates, which diflfer greatly in size, 

 proportions and colour in various species. Plates to the 

 number of two or three hundred are attached to their 



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