Orcas – Killer Whales Of The San Juan Islands
The Orca is the largest representative of the dolphin family (order Cetacea, subfamily Delphinidae) and a versatile predator. It is also recognised as a Killer Whale or Great Killer Whale, even though it is not a whale. The actual Killer Whale identify is really a corruption of the older Killer of Whales, the species is actually well-known to prey on young and tiny cetaceans. Another phrase for the orca is Grampus.
Characteristics:
The orcas are usually distinctively marked, with a white chest and sides, black back and a white patch above and behind the eye. They have a heavy and stocky physique and a considerable dorsal fin. Males can be up to nine and a half meters in length (in excess of 31 ft) and weigh as much as ten tons; females are smaller, attaining 8.5 metres (about twenty eight ft) at most and a weight of seven or eight tons. Calves at birth weight about one hundred and eighty kilograms and are about 2.4 metres in length (about 8 ft). At about 1.8m (about six feet), the dorsal fin of the male is taller than the female’s, and also much more up-right. From a distance, juveniles and females can be confused with various dolphin and porpoise species.
Range and distribution:
Most killer whales live in the polar zones however they’re found in all oceans including the Mediterranean and Arabian Sea as well as the Gulf Islands in the United states and British Columbia, Canada. At sea they’re typically observed in pods of 5-25 animals, though groups of as much as 150 have been observed together.
Diet :
An Orca’s diet is based on completely on supply, though pods can specialise and therefore ignore possible feed. It is believed that they need around 60 kilograms of nutrition daily. Their prey comprises 20 species of cetaceans, 5 species of pinniped (sea lions), thirty species of fish (specially salmon), seven kinds of birds as well as two species of squid, in addition to a selection of additional sea creatures, occasionally including bigger whales like Fin Whales, Minke Whales, Gray Whales, or even youthful Blue Whales. Orcas will even seek out and kill Great White Sharks for their nutrient rich livers as well as to eliminate the competition for meals. It’s from their assaults on whales that they acquired their name; they do not attack people.
Orcas and man :
Orca are deemed to be too small for commercial whaling, however they are occasionally killed simply because they are competing with humans for fish. In the 1950’s the USAF, at the request of the Icelandic government utilised bombers and gunners to slaughter orcas in Icelandic seas. The operation was regarded as a terrific success at the time.
In recent years, the orca’s intelligence, trainability, striking look and playfulness in captivity have made orcas a popular public aquarium or zoo attraction. This, combined with the simple fact that the animal just isn’t hostile towards humans, has contributed to the image of the species being rehabilitated from an object of fear such as Great White Sharks to a respectable predator, deserving of toleration. Orcas in aquariums may develop pathologies such as dorsal fin collapse, witnessed in over 60% of captive adult males.
