On the External Characters of the Blackfish or Pilot Whales (Genus Globicephala)

The coloration and morphometry of the north Atlantic pilot whale Globicephala melaena melaena are described and comparisons made with the subspecies G. m. edwardi, occurring in the southern oceans, the tropical Atlantic G. macrorhyncha and the north Pacific G. scammoni. The north Atlantic pilot whale may show small differences in color pattern from the southern subspecies but no differences have been detected in morphometry. The other two species have dark ventral markings of approximately the same form as G. melaena. The flipper of G. melaena grows more rapidly in length than the body throughout all but earliest postnatal life, while the flipper of G. macrorhyncha is isometric. The latter species thus has a shorter flipper at all except young ages. G. scammoni appears to be intermediate in this feature. G. melaena shows positive allometry of the flipper and dorsal fin in foetal and most of postnatal life but negative allometry between birth and weaning. The functional significance of this feature, found also in the fin whale, is not yet clear.