AQUATIC MAMMALS 



words, they prefer the smallest food they can get. I am unaware of the 

 method they employ in securing fish as large as one-foot mackerel, but 

 have been told of how the humback (Megaptera) obtains them. An ex- 

 perienced and trustworthy whaler has assured me that off the coast of 

 Lower California he has often watched these whales feeding on fish of 

 this size. According to him, they "stand on their tails" in the water 

 with snout protruding, presumably in a dense school of fish. With 

 mouth opened at a right angle the water is fanned with the greatly 

 elongated flippers and the fish (according to his theory) mistaking the 

 dark cavern of the great mouth for a safe haven, rush thither. During 

 this process he assurred me that the mandible was twisted from side to 

 side in so outlandish a fashion that it was a wonder the animal could 

 ever get it back into place. Then with a heave, the whole head was 

 lifted above the surface, and as the jaws were closed, fish and water cas- 

 caded from the mouth. I believe this statement, but give it for what it 

 is worth. Certainly fish of this size must be secured after some other 

 manner than that employed in catching shrimp. The bow-head whale 

 is said to feed largely on jelly-fish of several sorts. This larger fare, 

 being less crowded in the water, may have had something to do with 

 the development of the enormous head, which may reach one-third of 

 the total length, or it may be because of some other stimulus. 



In the Mysticeti the tongue is of two distinct sorts. In the balaenid 

 whales and the gray whale it is of large size, apparently even higher 

 than broad, firm and highly muscular. It is not a fortuitous accom- 

 paniment that in these animals the external throat is either entirely 

 without furrows or practically so {Rhachianectes has two or three short, 

 shallow grooves, and it is of interest to note that among the toothed 

 whales this is also the case in the Ziphiidae) . This indicates that the 

 gular region is not extensible, and it does not need to be. When, while 

 feeding with the mouth partially opened, it is wished to swallow the 

 food that has been captured, all water is forced from the mouth by sim- 

 ply elevating the tongue, just as we ourselves would do. 



This procedure in whales with grooved throats (at least in Balaenop- 

 tera, and probably others) is entirely different. It has been frequently 

 stated in the literature that the tongue of these whales is enormous. Of 

 course it is, in an animal of this size, but not relatively so. On the 

 contrary it is extremely small and so weak that it may really be con- 

 sidered as nonfunctional. In an eleven-foot fetus of Balaenoptera the 

 tongue was slightly muscular (considerably less so than in the normal 

 mammal) — much more so than in the adult. It almost filled the mouth 



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