METABOLISM 3OI 



Sperm Whale that was paralysed by a harpoon after an intense chase. 

 The figure he obtained, i.e. 100-7° F-, must, however, have been abnor- 

 mally high, as w'as the temperature Portier took of a recently killed Killer 

 (98° F.), even though Tomilin took similar temperatures in Black Sea 

 Dolphins (97-7° F.). White measured 95° F. in a porpoise, and Richard 

 96-1° F. in a dolphin. These figures agree with Laurie's (1933) average of 

 95° F. in thirty freshly killed Blue and Fin Whales. Parry, Kanwisher 

 (1957), and Slijper took temperatures of 95-9° F. which agreed with those 

 taken by Guldberg in 1900, so that Sudzuki's 97-9° F.-98-6° F. is probably a 

 little on the high side. However, Sudzuki worked with N. Pacific Sei 

 Whales, while the other biologists worked with Blue and Fin Whales. 

 For the time being, at least, we may take it that the average body tempera- 

 ture of Cetaceans in general is about 95-9° F. - a very low figure indeed for 

 a mammal. 



This figvu'e is 2-5° F. below that of man, w'hose temperature is low in 

 turn when compared wdth that of horses (100-4° F.), of cows and guinea- 

 pigs (ioi-3°F.), of rabbits, sheep and cats (102-2° F.), and of goats 

 (i03-i°F.). Only hedgehogs are known to have an average summer 

 temperature eqvial to that of Cetaceans, while sloths, opossums and 

 duck-bills (89-6° F.-93-2° F.) are even more cold-blooded. But then the 

 last-named species occupy such a special position among mammals in so 

 many respects, that we may safely say that compared with terrestrial 

 mammals, whales have a very low temperature. Seals and related species 

 certainly have higher temperatures, for Clarke measured 98° F. in an 

 elephant seal. The hippopotamus, on the other hand, has a temperature 

 similar to Cetaceans (96° F.), and sea-cows probably have a lower 

 temperature still. It may be regarded as most advantageous to Cetaceans 

 that their body functions optimally at so low a temperature, since the 

 smaller the difference from the aquatic environment, the less heat (and 

 consquently food) is needed for maintaining thermal equilibrium. 



Since heat is lost through the skin, it is important to determine the actual 

 size of the integument. Little is known about this subject apart from the 

 fact that surface areas of 12-4 and 14-5 square feet have been measured 

 in porpoises, of 15-2 square feet in a Common Dolphin, of 143 and 146 

 square yards in Fin Whales and of 223 square yards in Blue Whales. 

 While the skin of the Blue Whale would therefore cover a tennis court, it 

 is, nevertheless, relatively small compared with the animal's bulk. Thus 

 an elephant whose skin has an area of about 41 -8 square yards would, if its 

 mass were as great as a Fin Whale's and its skin surface rose in proportion, 

 cover an area of 480 square yards. Similarly, an average porpoise has a 

 smaller surface area than a man of approximately equal weight, whose 

 skin covers 19-3 square feet. This comparatively much smaller area of the 



