Orcinus orca
At a length of nine metres and weight of over five tonnes, the Killer Whale, Orcinus orca this is the largest member of the dolphin family. A strikingly marked animal characterised by a body pattern of dramatically contrasting areas of intense black and white. The rounded head, indistinct beak, large pointed teeth and prominent upright dorsal fin complete what is considered one of the oceans most impressive mammals. There is probably no other cetacean so appropriately named.
The Killer Whale is found in all oceans and seas of the world usually in family groups. They occur in most habitat types from coastal areas to the deep ocean waters, from the tropics to polar regions.
The Killer Whale has never been the target of serious commercial hunting so the species worldwide is secure. There is some concern about depletion of individual populations and disruption to social structure from captures for the oceanarium trade and limited hunting in some parts of Asia, Northern Europe and the West Indies.
These animals are serious meat eaters and one of the most efficient large predators of the ocean. A cooperative hunter, they often work in packs, and will take a broad range of vertebrates including whales, seals, penguins, fish, sea otters, and turtles. Killer Whales have marked territorial behaviour and home ranges. Their prey is determined by what is available in their home range but they also seek out areas of seasonal abundance such as seal pupping sites.
Killer Whales are a highly social species whose group size and composition is based on the dominance of a female line. The gestation period is thought to be about 15 months after which a single young is born. Group cooperation extends to care of the young, which will continue to suckle from the mother for an extended period of up to two years. The breeding season is variable, as is the interval between births. This latter period can be as little as three years or as long as eight.
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