A killer whale (Orcinus orca) is a marine mammal of the family Delphinidae (oceanic dolphin). Also known as orca, it is a highly predatory black-and-white toothed whale, which has a large erect dorsal fin. It is an apex predator, which means it is at the top of the food chain in the world's seas and oceans. However, killer whales are not aggressive to human beings as no attacks on them have been registered both in the open oceans or near the coasts. Despite the fact that they are ferocious predators, they also are highly social and intelligent mammals, which are endowed with a large brain. Their populations consist of matrilineal family groups, which is the tracing of kinship through the female line.
Physical Description
The males of the killer whale reach 10 m in length and weigh as much as 8 tons. The females, on the other hand, reach 7 m in length and weigh as much as 4 tons. The back and sides of the animal are black, with a white throat, and there is a white wide stripe down the abdomen. There is a white spot over each eye and, in the male, above the dorsal fin. The pectoral fins are blunt and broad, and the dorsal fin is high (to 1.7 m in males and 0.9 m in females). Their jaws have 40 and 52 large pointed teeth. As mammal, their body temperature is also between 36° and 37° C. Together with some species of dolphins, the orca is the fastest swimmer of the oceans, being able to reach the top speed of 56 km/h (35 mph).
Since they are mammals, they have both lungs and mammary glands. They exhale carbon dioxide (CO2) and breath in atmospheric air through an orifice on top of their head, called blow-hole, when they surface. The females breastfeed their young (calves) by releasing the milk through their mammary slits when the calf rubs its snout against the mother belly where the mammary glands are located. The gestation period of the embryo/fetus lasts about 16 months. The calf is between 2.1 and 2.8 m long at birth. The animal lives up to 50 years. Males reach sexual maturity at a length of 5.8 m; females, at 4.9 m.
Natural environment (habitat)
The killer whale is a cosmopolitan animal, meaning it is found from the equator to the ice of the arctic and antarctic. It is is also found commonly in the waters of the northern Pacific Ocean off the coasts of Kuril Islands and the Komandor Islands. There are none in the Laptev and Black Sea. They are also spotted in the cold waters of the southern Atlantic Ocean off the coasts of Patagonia. The killer whales stay in small herds. They feed on fish, cephalopods, and marine mammals, such as seals and sea otters. Only the large males attack other whales, and this only rarely. The killer whale is voracious, although not dangerous to man. It can live for long periods in captivity, in pens and aquariums. The animals eat up to 160 kg offish per day.
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| Above, a male orca breaches off the coast of Patagonia. |
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| The relationships built between killer whales of the same pod lasts for life. |