The Killer whale is a fairly large mammal. They grow up to lengths of 35ft and can weigh up to 10 tons. The males usually grow larger than the females. Females usually only reach about 28ft, weighing as much as 8 tons. The males reach between 10 and 11 tons.
Orca bodies have distinctive black and white markings.
Both females and males have similar markings except on the underside, where it is possiable to distinguish male from female. The dorsal fin also distinguishes male and female adults. In the mature male the erect dorsal fin may reach a height of 5.5ft but the female dorsal fin grows only to an average of 3ft. They have a tail, falcate, dorsal fin and large paddle-like flippers. Orcas are one of the toothed whales.