THE SPERM WHALE 123 



scratches 2-3 m. in length and appear to be of more frequent occurrence than sucker 

 marks (Plate VIII, fig. 3 ; Plate X, fig. 2). In female Sperm whales it is uncommon to 

 find scars caused by large cephalopods. It thus appears that the females, being much 

 smaller than the males, usually feed on small cephalopods and do not attack the large 

 ones as do the males. 



In addition to cephalopods, seven stomachs contained the remains of fishes, some of 

 considerable size. Beale ( 1 839) states that fishes are only eaten in inshore waters : whether 

 this is correct or not they evidently form only a small part of the diet. The same author 

 states that the Sperm whale when feeding remains still and opens its mouth, letting the 

 lower jaw hang down, and swallows the cephalopods which are attracted by the white 

 teeth and light-coloured lining of the mouth. The great activity and agility of cephalopods 

 leads one to think that there may be some truth in this theory, which is supported by 

 the fact that in the Mediterranean and elsewhere cephalopods are caught on unbaited 

 hooks painted white. Although seldom seen, or taken in zoological collecting gear, 

 cephalopods of many species must be very abundant in the upper layers of the sea, as 

 is shown by the stomach contents of Sperm whales and also by those of seals and 

 oceanic birds (Matthews, 1929). 



BLUBBER 



Data on the blubber are available from seventy-three Sperm whales, mostly males. 

 The blubber thickness was measured on the flank and varied between 8-5 and 15-5 cm. : 

 the dorsal blubber is thicker than this and was measured in a few whales, the thickest 

 recorded being 33 cm. Figs. 32 and 33 show the relation between blubber thickness and 



10 12 14 IS 



Total Leng'th in metres 



Fig. 32. Sperm whale. Males. Thickness of blubber and total length. 



length of whale for males and females. The catches of males at South Georgia are separ- 

 ated from those at South Africa in Fig. 32: Fig. 33 shows females from South Africa 

 only, because they are not found at South Georgia. These figures show that blubber 

 thickness appears to increase fairly constantly with length for adults of both sexes, but 

 that in immature whales, of which males only were examined, the blubber is pro- 

 portionately thicker. This is shown with greater clearness in Fig. 34, where blubber 



