EXTERNAL CHARACTERS OF BLUE WHALES 273 



The largest Blue whale measured by us was No. 667. This was a female 28-5 m. 

 long, or 93 ft. 6 in. Only two others measured 28-0 m. or over (No. 1281, 28-2 m., and 

 No. 1417, 28-0 m.), but there were ten measuring between 27-0 m. and 28-0 m. All 

 these were females. The method of measuring the total length from the tip of the snout 

 to the notch of the flukes is the shortest measurement which could be called the total 

 length, and it has already been explained that this is appreciably shorter than the 

 overall length. One would therefore hardly expect to find a whale measuring 100 ft. 

 (30-48 m.) according to this method, but if the projection of the lower jaw beyond the 

 snout, and the tips of the flukes beyond the notch are included in the measurement, 

 100 ft. is not at all an improbable length for a Blue whale. The largest whale measured 

 by Barrett-Hamilton at South Georgia was 95 ft. long, but this was taken from the 

 notch of the flukes to the tip of the mandible. The length to the tip of the snout was 

 92 ft. This appears to be the longest measurement ever made up till now which can 

 really be regarded as authentic. In a recent paper based on the statistics of the Nor- 

 wegian Whalers' Association, Risting (1928) quotes five instances of Avhales measuring 

 100 ft. or more. The measurements, however, appear to be unreliable, for according 

 to Risting's data the smallest pregnant Blue whale measured 63 ft. or 20 m. (allowance 

 being made for Norwegian feet) and 11-4 per cent of the 71 ft. (22-5 m.) whales were 

 pregnant. Now Blue whales are rarely adult at a length of less than 23-5 m. and it is in 

 our opinion extremely improbable that 11-4 per cent of those measuring 22-5 m. were 

 pregnant, or that a 20-0 m. Blue whale could be pregnant, and it must be supposed 

 that some of the measurements were inaccurate. 



The size of the Blue whale is also discussed at some length by True (1904) who 

 concludes that the maximum authentic measurement of a Blue whale from the North 

 Atlantic is 88 ft. 7 in. or 27-0 m. Authentic measurements from the South Atlantic 

 were not to be had at that time and it appears that in the North Atlantic the 

 whales in general do not attain to so great a size as in the south. More recently, 

 however, a huge Blue whale, said to measure 98 ft., was killed in the Panama Canal, 

 and Harmer (1923), from an examination of the cervical vertebrae, estimates that the 

 reputed length was not exaggerated. The fact that the average size of the Blue whales 

 of South Georgia is considerably greater than that of the corresponding form in the 

 North Atlantic is commented on by Hinton, who suggests that if it could be shown 

 that the Blue whales of the two regions do not mingle in equatorial waters, the diff'er- 

 ence in size might be regarded as sufficient ground for recognizing the two forms as 

 distinct sub-species. In the same paper, however, Hinton mentions that the small size 

 of the whales examined by True at Newfoundland suggests that during the whaling 

 season the herds in that region consist principally of adolescent individuals with a 

 few young adults. In view of the fact that at south-west African stations the average 

 size of the whales is extremely low, solely on account of the high percentage of immature 

 whales which are caught there, it does not seem impossible that a similar factor may 

 operate in more than one part of the North Atlantic and that the comparatively small 

 average size of the whales taken there may be due to a high percentage of immature 

 whales in the catches. 



