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Friday, April 12, 2013

Wildlife Photography - Killer Whales, Orcinus orca

Orca, also known as the Killer Whale, is the largest member of the dolphin family and a favorite animal for whale watching groups all around the world. The Killer Whale’s strikingly marked black and white body is unmistakable, being black on the upper parts, sometimes with a light grey ‘saddle patch’ behind the dorsal fin, and white on the under parts, lower jaw and undersides of the tail. White lobes extend up the sides of the body behind the dorsal fin, and there is a white, oval patch behind each eye. In newborn Orcas, the white areas of the body have an orange hue.

Both the male and female Killer Whales have a broad, rounded head and snout, an enlarged forehead, large, paddle-shaped pectoral fins and a large dorsal fin. However, males grow larger than females, and on reaching maturity become stockier and develop disproportionately larger fins, with adult males easily recognized by the tall, erect dorsal fin, which is the largest of any cetacean, growing to an impressive 6 feet in height. The female Orca, by contrast, has a more backward-curving dorsal fin , which grows to about 3 feet in height. An Orca’s dorsal fin and saddle patch are unique to each individual.

A number of different forms of Killer Whale have been identified, which specialize in different types of prey, differ in appearance, behavior and habitat use, do not associate with each other and are not known to interbreed. Studies have also revealed genetic differences between the different forms, and the Orca may therefore be split into a number of different subspecies or even distinct species in the near future.

Orcas are very sociable animals, they communicate using a variety of screams, clicks and whistles, in addition to physical behaviors like breaching, slapping the flippers and tail, and spyhopping. Click-like sounds are also used for echo location. An Orca pod may consist of up to 40 or 50 individuals, and can get even larger if several groups temporarily join together. The group structure of a pod of Killer whales is complex. In a group of ‘resident’ Orcas, the unit is led by a mature female, her daughters and their offsprings and some male offsprings. The group is bound by very strong bonds and stay together for life, although they mate outside of their immediate pod.

Killer whales are found in all the world’s oceans. Some pods may migrate, probably following the movements of their prey species. The greatest threat to Orcas comes from pollution and degradation of their habitat. As a top predator, the Orca is particularly vulnerable to the accumulation of contaminants in its tissues. Oil spills can also harm their ability to survive and reproduce as their prey may be adversely affected by their environment.

Visit my website to see more photos of Orcas and other great whales from around the world, view a video on these magnificent animals and read my article to get some tips on whale photography and watching on the high seas.

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