EVOLUTION AND EXTERNAL APPEARANCE 



87 



Figure ^j. Scars on I he skin of a porpoise caitg/it at the entrance to the Channel on jist 

 Janna)')' /95J. Photograph: IV. L. van Utrecht, Amsterdam. 



direct evidence of the identity of its perpetrator on its skin. The biologist 

 has had to turn detective, trying to sift what chies he can from the available 

 circumstantial evidence. 



In this process, what strikes him is the fact that no skin-wounds ever 

 occur in species which keep exclusively to cold seas, e.g. Right Whales, 

 Belugas or Narwhals. The cause must therefore be sought in warmer 

 waters, and this is, moreover, borne out by the fact that in migratory 

 whales caught in cold water the scars are always healed - open wounds 

 are only found in the tropics and the sub-tropics, and particularly 

 between approximately 45 degrees north and 15 degrees south. Between 

 the polar seas and these regions, the wounds are partially healed. 



The peculiar radiating pattern of the scars is associated with the 

 direction of the papillary layer between the epidermis and the dermis 

 (cf. Chapter 1 1 and Fig. 171). Hence it appears inost clearly in scars whose 

 axis is nearly perpendicular to the direction of the papillary layer of the 

 corium. 



Now, what inhabitant of the warm seas can possibly inflict these 

 wounds? The credit for having found an acceptable solution must go 

 primarily to G. C. Pike, a biologist who spent many years on a lonely post 

 in the Pacific - the land station of Nanaimo on Vancouver Island (British 

 Columbia) - and did outstandina: research on whales. Pike discovered 



