THE SPERM WHALE 



97 



Table II. Sperm whale. Foetuses examined at South African 



Whaling Stations 



EXTERNAL CHARACTERS 



BODY PROPORTIONS 



The standard series of measurements was taken from eighty-one Sperm whales, but 

 in many the series was not complete for each measurement. Measurement No. 12, 

 " Notch of flukes to end of system of ventral grooves", applicable only to balaenopterid 

 whales, was omitted, but the standard numbering has been retained for the sake of 

 uniformity, so that No. 12 is missing. Measurement No. 2, "projection of lower jaw 

 beyond tip of snout ", has been altered to " projection of snout beyond tip of lower jaw", 

 because the lower jaw does not project as in the whalebone whales. The data obtained 

 are set out below and may be taken as a fairly good representation of the external 

 proportions of the Sperm whale, especially in the male. The figures derived from South 

 Georgia and South Africa have been combined, because it is now generally accepted 

 that there are no specific or subspecific differences between Sperm whales from different 

 places, and the present figures, shown below, confirm this view. The measurements 

 are shown in the Appendix (p. 165). 



A summary of the analysis of the figures is shown in Table III, in which the average 

 measurements, expressed as percentages of the total length, are given separately for 

 males and females. The number of measurements producing each mean is also shown. 



These average measurements show clearly the considerable sexual differences in this 

 species. In all the measurements relating to the head and anterior part of the body the 

 percentage values are markedly smaller in the female than in the male, and to set against 

 this the values for the posterior part of the body, as shown by the values for measure- 

 ments Nos. 10 and 11, are greater. The flipper of the female, too, is proportionately 

 slightly longer than that of the male, as shown by measurements Nos. 16 and 17. The 

 values for the measurements of the dorsal fin in the female are derived from too few 

 examples for comparison to be made. In addition, the values for measurement No. 13, 

 the genito-anal distance, are very much smaller in the female than in the male, owing to 

 the close approximation of the genital and anal apertures within a single groove of the 

 body surface, as recorded below. The female Sperm whale then, is considerably longer 

 in the tail region, when compared with the male, and shorter in the head region. 



