en.wikipedia.org/wiki/Killer_whaleWith a bit of extended Google research, in preparation for this whale season... I have just found out there are 4 types of Orca.
Mainly identified from their white eye patch...
Type A - medium sized white eye patch - typical American killer whale.
Type B - large white eye patch - feeds on seals
Type C - thinner slanted white eye patch (of asian appearance in humans!

) - this one is the Antarctic one, and I assume this is the one we would see in Australian waters.
Type D - very small white eye patch - the rarest Orca, not commonly sighted.
They are believed to be different sub species, not having bread together for around 10,000 years.