EXTERNAL CHARACTERS 243 



record of a larger female sperm whale: the International Whaling Statistics record females up to 

 55 ft. in length, but it is well known (Matthews, 1938, p. 142) that a male sperm whale with its penis 

 completely retracted is occasionally recorded as a female. 



It would appear then that the maximum sizes attained by sperm whales in the Azores are not less 

 than those attained by sperm whales elsewhere. 



EXTERNAL CHARACTERS 



Study of the external characters affords one means of examining the various stocks of sperm whales 

 for possible differences, a matter which will be further discussed on p. 286 ff. 



In sperm whales of the North Atlantic and adjacent seas the external characters have-been described 

 by several authors (Hentschel, 1910; Lillie, 1910; Hamilton, 1914; Cabrera, 1925; Wheeler, 1933; 

 Boschma, 1938; and Bolognari, 1949). Observations referring specifically to Azores whales are 

 recorded by Monaco (1888), Pouchet & Beauregard (1889), and Pouchet & Chaves (1890). All these 

 references concern one or a few whales: the present sample is larger, consisting of the whales 

 I examined in 1949 and the five small foetuses. 



In studying variation, the external characters likely to yield most profit are the proportional 

 . measurements, the colour of the body surface, the dorsal fin and the number of humps posterior to it, 

 and the number and pattern of grooves about the throat. 



Proportional measurements 



The body proportions of five foetuses and one adult whale are recorded in Table 3. To the standard 

 measurements it has been possible to add no. ga, the span of the flukes, because the widespread 

 modern practice of docking the flukes immediately after capture is not followed in the Azores. In 

 Table 3 the Azores measurements are compared with southern measurements from a male foetus in 

 the length group 0-1 m. and from several whales of 13-14 m., the appropriate material among southern 

 whales described by Matthews (1938, Table IV). It is unfortunate that proportional measurements of 

 only one Azores whale could be made in 1949, but the comparison, so far as it goes, does not seem 

 to establish any significant differences between the proportions of this individual and the range of 

 those in southern whales. As much can be said for the foetal measurements, except to note that nos. 24 

 and 25 show such large discrepancies so considerably at variance with other comparisons as to suggest 

 clerical errors here, or differences in interpreting the sense of measurements 24 and 25. 



Colour 



In Table 4 the markings of eighteen males and fifteen females have been classified into seven cate- 

 gories. Only one whale, a juvenile male 7-5 m. long, might be called entirely pigmented, being a 

 uniform iron grey colour except for slight streaking between the umbilicus and the penis slit. The 

 remainder had more or less white ventrally, or some light streaks or mottling. In a third of these the 

 unpigmented area was a ventral white splash, usually in the umbilical region, but occasionally limited 

 to patchy development around the throat region or the anus: the umbilical splash might be a small 

 white knot, or flaring out on either side of the middle line as two horns or flags of whiteness directed 

 posteriorly, or more extensive and stretching from umbilicus to reproductive aperture. About as 

 many whales had white or light grey ventro-lateral streaks or flecks, of more or less extent, brushing 

 out from the umbilicus backwards,* although sometimes sending an arm of diffuse streaking forward 

 to the insertion of the flippers on either side. In 15% of the sample the last two categories were 



* The 'umbilical whorl' of Matthews (1938, p. 109). 



