Orcas Called Killer Whales?? Killer whale/orca male (resident)The orca, or killer whale, with its striking black and white colouring, is one of the best known of all the cetaceans. It has been extensively studied in the wild and is often the main attraction at many sea parks and aquaria. An odontocete, or toothed whale, the orca is known for being a carnivorous, fast and skilful hunter, with a complex social structure and a cosmopolitan distribution (orcas are found in all the oceans of the world). Sometimes called “the wolf of the “sea, the orca can be a fierce hunter with well-organized hunting techniques, although there are no documented cases of killer whales attacking a human in the wild.
FAMILY: DelphinidaeGENUS: Orcinus
Physical Description of killer whale
The orca has a striking colour pattern made up of well-defined areas of shiny black and cream or white. The dorsal (top) part of its body is black, with a pale white to grey “saddle” behind the dorsal fin. It has an oval, white eyepatch behind and above each eye. The chin, throat, central length of the ventral (underside) area and undersides of the tail flukes are white. Each whale can be individually identified by its markings and by the shape of its saddle patch and dorsal fin.
Fins and Fluke
Another distinctive feature of the orca is its dorsal fin, which can reach 6 feet (1.8 m) high in males and is shaped like an isosceles triangle. The immature male and the female dorsal fins are also large, reaching 3 feet (.91 m) high, but are curve. The dorsal fin often has identifying nicks, cuts, scars and indentations. The paddle-shaped pectoral flippers are broad, rounded, and can reach a length of nearly 6 feet (1.8 m) and a width of 3 feet (.91 m).
Length and Weight
Males can grow as large as 32 feet (9.6 m) long and weigh 8 to 9 tons. Females can reach 23 feet (8.2 m) in length and weigh up to 4 tons.
The mouth of the orca is large and well adapted for hunting. It has 46 to 50 conical shaped teeth that point slightly backwards and inwards. The upper and lower teeth interlock, which aids in gripping large prey and tearing it into smaller pieces for easier swallowing.
Depending on the population and geographic area, the diet of orcas varies. Food preference and availability may have led to the distinct population types, such as resident, transients, and offshores that have been observed/identified in the Pacific Northwest region of the United States and other areas around the world. Generally speaking, transients will feed on a variety of animals including sea lions, elephant seals, harbour seals, porpoises, squid, sharks, fish, penguins, smaller whales, such as belugas and narwhals and even large baleen whales, such as grey whales. Resident whales tend to feed primarily on fish species such as salmon or herring. The diet of offshores is still being studied by scientists.
Mating and Breeding
Little is known about the orca’s breeding habits. Newborn calves have been observed throughout the year suggesting that that mating can occur at any time with no particular breeding season. In the wild, orcas become sexually mature between the ages of 10 and 18 years of age and are thought to be actively reproducing by the time the male reaches about 20 feet (5.1 m) in length and the female reaches about 16 feet (4.1 m). Based on long-term field studies, females are believed to be reproductively active into their early 40’s. The maximum age for males is unknown.
Captive females can bear a calf every two years, but a more typical period between calves in the wild is 3 to 5 years. The gestation period is estimated to be between 13 to 17 months. At birth, a calf is generally about 6-7 feet long (1.8-2.1 m) and weighs around 400 pounds. However, calf size and weight does vary slightly between populations/regions
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