The Shark That Hibernates ' 



By L. Harrison Matthews, F.R.S. 

 Scientific Director, Zoological Society of London 



The basking shark is among the largest of living fishes for it 

 reaches a length of nearly 30 feet and a weight approaching 4 tons ; 

 only the great whale shark of tropical seas exceeds it in length and 

 bulk. Basking sharks are found in all the oceans of the world except 

 the coldest, but it is not certain, although it is probable, that they are 

 all of one species ; those that live in the North Atlantic belong to the 

 species Getorhinus maximus. The basking shark is common in the 

 seas of western Europe, at least during the summer months, and is 

 conspicuous when it approaches the shore and swims so near the sur- 

 face that its enormous back fin sticks out of the water. The habit of 

 swimming slowly at the surface has given rise to the common name of 

 the animal (although it does not literally bask) and to the alternative 

 local name of sailfish. In spite of its great size, comparative abun- 

 dance, and frequent conspicuousness little was known of the anatomy 

 and less of the natural history of the species until recent years — and 

 many questions have still to be answered. 



My own special interest in the basking shark dates from 1947, 

 when Dr. H. W. Parker and I were invited by Maj. Gavin Maxwell to 

 visit his shark fishery in the Hebrides to study its biology. Our in- 

 vestigations produced much unexpected information. 



The body of the basking shark is fusiform or cigar shaped, with the 

 greatest diameter about one-third of the body length behind the tip 

 of the snout. Two large triangular fins are set on the back, the front 

 and larger one nearly 6 feet high a little in front of mid-length, the 

 smaller one nearer the root of the tail below which there is another 

 small triangular fin. The tail fin is very large and is asymmetrical, the 

 upper lobe being the bigger; it is crescentic in outline and measures 6 

 feet or more from tip to tip. The paired pectoral fins are also very 

 large, their leading edges measuring between 5 and 6 feet. In life 

 they are held more or less horizontally and act as planes supporting 

 the front part of the body which, without them, would be driven 



^ Reprinted by permission from the New Scientist, No. 280, Marcli 29, 1962. 



415 



