Killer Whale, Orca  |  

Killer Whales are the largest member of the dolphin family and are recognisable by their distinctive black, white and grey coloration. The head is rounded, with no distinct beak. A white eye patch, or spot, is located just above and behind the eye. Just behind the dorsal fin is a grey saddle patch. The Killer Whale’s belly, lower jaw and the underside of the tail flukes are white. The rest of the body is black. The wide, tall dorsal fin is curved backwards in females and is more upright and triangular-shaped in males. The pectoral flippers are paddle-shaped. In addition to sexual size dimorphism, male Killer Whale appendages are disproportionately larger than in females. Adult male and female Killer Whales attain weights exceeding 4000 kg and 3100 kg, and lengths of 9.8 m and 8.5–9.2 m, respectively. Although groups of up to several hundred individuals have been observed, group size is usually less than 30, and several studies outside Australian waters have reported mean pod sizes of less than 10. Off southern Australia, group size can be up to 52 individuals, although most sightings report less than 10. Long-term studies in the north-western Pacific have shown that pod composition appears to remain consistent over time; about 20% are adult males, 40–50% adult females and 30–40% immatures and juveniles. A social hierarchy exists within the pod.