COMPARISON WITH EARLIER ACCOUNTS i35 



appearance has not had its origin on board. Apart from these, and in spite of the close attention that 

 has been paid to the subject during this commission, no other noises have been identified with the 

 whales. 



Asymmetrical pigmentation of Fin whales 



An account of the pigment distribution in Fin whales has been given by Mackintosh and Wheeler 

 (1929), and attention is directed to the asymmetrical arrangement of pigment on the jaws (p. 354). The 

 report also makes an interesting speculation on the possibility that Fin whales might swim slightly on 

 their right side while under the water. 



The suggestion is based, presumably, on the analogy of Thayer's ducks, according to which the 

 shadowed and the highly lit aspects of an animal are differently pigmented ; or ahernatively there is 

 the theory that the more exposed portions of the whale may be pigmented as a protection against the 

 action of the sun's rays. In either case a regular turning on to the right side might reasonably be 

 expected. 



Of the many whales watched, a vast majority broke surface and sounded on an even keel. Moreover, 

 of the whales which turned on to their sides when ' boltering ' or when raising a single fluke above the 

 surface, some were on their right side, others on their left. As far as they go, the observations give no 

 evidence of habitual twisting in the water and the asymmetrical distribution of pigment remains a 

 problem. 



SUMMARY AND CONCLUSIONS 



1. The habits, swimming manoeuvres, bodily movements, respiratory rhythm and reactions of fin 

 whales have been noted during a programme of whale marking operations near South Georgia. The 

 observations were made between Dec. loth and Feb. 9th, 1936-7. At this season the whales are 

 knovm to be feeding. 



2. An observed reaction to the presence of the ship has been an alteration in the respiratory rhythm, 

 but other changes of behaviour are likely. Difficulties of observing whales at a distance are pointed 

 out and the view obtainable from the decks of a catcher might give rise to a wholly erroneous picture 

 of the ways of the unmolested animal. With these reservations the following deductions have been 

 made. 



3. The way the whale breaks surface to breathe and submerges again is analysed into its component 

 movements. In the process of submergence the body may travel forwards with the body extended, 

 or downwards with the body doubled. The latter was the most usual and the structure of head, dorsal 

 fin, peduncle and flukes are shown to be particularly adapted for this action. Breathing requirements 

 impose a need to overcome mechanical difficulties not met with by fish. Quick visits to the surface 

 would seem to involve certain mechanical difficulties which these adaptations are designed to overcome : 

 and this specialization for dorsi-ventral turning has resuhed in the peculiar habit of feeding on the side. 



REFERENCES 



Allen, G. M., 1904. Some observations on rorquals off Southern Newfoundland. Amer. Naturalist, xxxvni, no. 453, pp. 613-23. 



1916. The whalebone whales of Nezv England. Mem. Boston Soc. Nat. Hist., viii, no. 2, pp. 107-322. 



Anderson, ]., 1746. Nachrichten von Island, Gronland und der Strasse Davis. Hamb., Frankft. u. Leipzig. 



Andrews, R. C, 1909. Observations on the habits of the Finback and Humpback whales of the eastern North Pacific. Bull. 



Amer. Mus. Nat. Hist., xxxvi, pp. 213-26. 

 Brown, R., 1868. Notes on the history and geographical relations of the Cetacea frequenting Davis Strait and Baffin's Bay. 



Proc. Zool. Soc. Lond., xxxv, pp. 533-56. 

 Bucket, G., 1895. Ouelques observations sur les Balenopteres des eaux islandaises. Bull. Soc. Zool. France, xx, pp. 30-1. 

 CoLLETT, R., 1886. On the external characters of Rudolphi's Rorqual (Balaenoptera borealis). Proc. Zool. Soc, pp. 243-65. 



