Abstract:
Killer whales Orcinus orca occur worldwide in a number of morphotypes that differ in size, pigmentation, acoustic
behaviour, food type and genetics – some may indeed warrant subspecific or even specific status. Until recently, all
killer whales in South African waters were referred to a single morphotype, Type A, but three individuals (two males
and one female) that have stranded since 1969 differ in several respects from other killer whales examined from
the region. Adult length is some 1–1.5 m smaller, appendages such as dorsal fin and flippers tend to be relatively
larger, and tooth wear is excessive. Although dietary information is scant, one stomach contained the remains of
several elasmobranchs, identified from a DNA subsample as blue sharks Prionace glauca, a dietary item that, if
habitual, might account for the tooth wear. This morphotype, referred to here as ‘flat-toothed’ and which in several
respects resembles the offshore form in the North Pacific and the Type 1 form in the North Atlantic, does not seem
to have been recorded previously from the Southern Hemisphere.
