156 



DISCOVERY REPORTS 



The whalers of Natal are of the opinion that there is a decided migration of Sperm 

 whales from the north in the early (southern) spring, and that it is then that females are 

 taken in large numbers. If this is so it may be inferred that the smaller peak in April 



Sep Oct Nov Dec Jan Feb Uar Apr Maq 

 Fig. 65. Sperm whale. Males. Monthly catches at South Georgia and the South Shetlands. 



Table XVI. Sperm whale. Occurrence of diatom film on whales 



at South Georgia 



represents a return migration towards the equatorial waters in autumn. The figures 

 must, however, be accepted with great caution, because Sperm whales are not taken off 

 Natal when Blue and Fin whales are available, and further, male Sperm whales are 

 always taken in preference to females because of the small size of the latter. Now the 

 drop in the curve for female Sperm whales and the shelf in the curve for males occur in 



