Killer whales are very social, some population consisting of matrilineal family groups the most stable of any animal species. Sophisticated hunting techniques and vocal behaviors, which are often specific to a particular group and traffic generation, has been described as manifestations of culture.
IUCN when assessing the conservation status of orca as the lack of data due to the possibility that two or more types of killer whales are a separate species. Some locals are considered threatened or endangered due to prey depletion, habitat loss, pollution (by PCBs), capture for marine mammal parks, and conflicts with fisheries. At the end of 2005, the "southern resident" killer whale populations that inhabit British Columbia and Washington state waters placed on the U.S. Endangered Species list.
Wild killer whales are not considered a threat to humans, although there are cases of captives killing or injuring their handlers at marine parks. Killer whales feature strongly in mythology indigenous cultures, with their reputation ranging from becoming the human soul for the killer mercilessly.
Type
Three to five types of killer whales may be different enough to be considered different races, subspecies, or possibly even species. The IUCN reported in 2008, "The taxonomy of this genus is clearly require review, and the possibility that O. orca will be split into several different species or subspecies for at least the next several years." In the 1970s and the 1980s, research off the west coast of Canada and the United States identified the following three types:
Resident: These are the most frequently seen of the three populations in the coastal waters of the northeast Pacific. People's diet consists mainly of fish and sometimes squid, and they live in complex family groups called pods and cohesive. Special female population was rounded dorsal fin Tips stop in sharp corners. They visit the same areas consistently. British Columbia and Washington's population is one of the most intensive marine mammals studied. Researchers have identified and named over 300 killer whales over the past 30 years.
Transient: The diet consists almost entirely of whale marine mammals. Transients generally travel in small groups, usually of two to six animals, and have less persistent family bonds than residents. Transients vocalize in less distinct dialect and less complex. Transient woman marked with more rounded dorsal fin and pointed out the population. District of gray or white around the dorsal fin, known as the "saddle patch", often contains some black color in the community. However, the saddle patches of transients are solid and uniformly gray. Transients roam wide along the coast, a few individuals were seen in both southern Alaska and California. Transients also known as Bigg killer whales in honor of Michael Bigg. The term has become more common and eventually replace the label transients.
Offshore: A third population of killer whales in the northeast Pacific was discovered in 1988, when a humpback whale researcher observed them in open water. As the name suggests, they travel far from shore and feed primarily on fish school. However, because a large dorsal fin and hollow scar resembling those of mammal-hunting transients, they may also eat mammals and sharks. They mostly have been found off the west coast of Vancouver Island and near the Queen Charlotte Islands. Offshores usually congregate in groups of 20-75, with occasional sightings of larger groups of up to 200. Currently, little is known about their habits, but they are genetically distinct from residents and transients. Offshores looks smaller than the other, and women who are characterized by dorsal fin tips that continue to be rounded.
Other populations has not been well studied, although specialized killer whale fish-eating and mammal-eating have been distinguished elsewhere. Separate populations of fish-eating and mammal-eating killer whales have been identified around the United Kingdom. Fish-eating killer whales in Alaska and Norway have people like social structures, while mammal eating killer whales in Argentina and the Crozet Islands behave more like transients.
Three types have been documented in the Antarctic. Two dwarf species, named Orcinus nanus and Orcinus glacialis, described for the year 1980 by Soviet researchers, but most researchers Cetacea skeptical about their status, and connect it directly to the types described below confidential.
- Type A looks like a whale "special" killer, a great shape, black and white with white secondary blindfold, living in open water and feeding largely on minke whales.
- Type B is smaller than type A. Have a great white blindfold. A large part of the body is a medium dark gray, not black, despite having a dark gray patch called a "dorsal cape" stretching back from the forehead to just behind its dorsal fin. Pretty yellow colored white district. It feeds largely on seals.
- Type C is the smallest type and lives in larger groups than the others. Its blindfold special leaning forward, not aligned with the body axis. Like Type B, it mainly white and middle gray, with dorsal robe dark gray and yellow-tinged patches. Only observed prey is the Antarctic cod.
- Type D is identified based on photographs from 1955 mass stranding in New Zealand and six at sea sightings since 2004. This will be known by a very small lid white, shorter than usual dorsal fin, and a round head (similar to a pilot whale). Rate Spread geography seems to subantarctic waters between latitudes 40 ° S and 60 ° S. And although nothing is known about the diet type D, is believed to include fish because groups have been photographed around the ship in which they were reported to hook Patagonian toothfish prey (Dissostichus eleginoides).
Types B and C live close to the ice pack, and diatoms in these waters may be responsible for the yellowish coloring of both types. Mitochondrial DNA sequences support the theory that recently deviate separate species. More recently, complete mitochondrial sequencing indicates two Antarctic groups that eat seals and fish should be recognized as a distinct species, as should the North Pacific transients, leaving the others as subspecies pending additional data.
This study is ongoing into the genetic relationships among killer whale types, and what sort of represent deep evolutionary trends. For example, killer whales eating mammals that old thinking probably closely related to other mammal-eating killer whales from different regions, but genetic testing argue this hypothesis.
Description
A special customized killer whale black bear back, white chest and sides, and a white patch above and behind the eyes. Calves are born with a yellowish or orange tint, which fades to white. Has a strong weight and with a large dorsal fin up to 2 m (6.6 ft). At the back fin, have a gray "saddle patch" behind the dark. Antarctic killer whales may have pale gray almost white on the back. Very special adult killer whale is not usually confused with any other sea creature.
When viewed from a distance, teens can be confused with other cetacean species, such as the false killer whale or Risso's dolphin. Killer whale teeth are very strong and sealed enamel. Gripping jaws are powerful tools, because the upper teeth fall into the gap between the lower teeth when the mouth is closed. Front teeth inclined slightly forward and to the outside, allowing the killer whale to withstand powerful pull motion of the prey while the middle and back teeth continue to remain in place.
Killer whales are the remaining members of the largest of the dolphin family. Men typically ranges between 6 and 8 meters (20 to 26 ft) long and weighing more than 6 tons (5.9 long tons, 6.6 short tons). Women are smaller, generally ranging from 5 to 7 m (16 to 23 feet) and weighing about 3 to 4 tons (3.0 to 3.9 long tons, from 3.3 to 4.4 short tons). The biggest killer whale on record man is 9.8 m (32 ft), weighing more than 10 tonnes (9.8 long tons, 11 short tons), while the largest female was 8.5 m (28 ft), weight 7, 5 tonnes (7.4 long tons; 8.3 short tons) [54]. Calves at birth weigh about 180 kg (400 lb) and about 2.4 m (7.9 ft) long.
Large size and strength of the killer whale made among the fastest marine mammals, able to reach speeds of over 30 knots (56 km / h). Frame structure delphinid killer whale is special, but stronger. Her integumentary, unlike most dolphin species to another, marked by a growing layer of dense networks fasikula dermal collagen fibers.
Killer whale pectoral fins are large and rounded, resembling paddles. Male pectoral fins are significantly larger than females. At about 1.8 m (5.9 ft) male dorsal fin is more than twice the size of her and more of a triangular shape-tall, elongated isosceles triangle-whereas hers is shorter and more curved. Men and women also have different patterns of black and white in their genital area. Sexual Dimorfisme also appears in the skull, adult males have long lower jaw of the female, and have greater occipital crest.
An individual killer whales can often be identified from the dorsal fin and saddle patch it. Variations such as nicks, scratches, and tears on the dorsal fin and the pattern of white or gray in the saddle patch are unique. Published directories contain identifying photographs and names for hundreds of North Pacific animals. Photo identification has enabled the local population of killer whales to be counted each year of the budget, and have allowed an insight into the life cycle and social structure.
White killer whales occur sporadically but rare among normal killer whales, they have been seen in the northern Bering Sea and around St. Lawrence Island, and near the Russian coast. In February 2008, a white killer whale photographed 2 miles (3.2 km) from Kanaga Volcano in the Aleutian Islands.
Killer whales have good eyesight above and below the water, good hearing and a good sense of touch. They have a very sophisticated echolocation abilities, detecting the location and characteristics of prey and other objects in their environment by emitting clicks and listening to the echo.
Range and habitat
Killer whales are found in all oceans and most seas. Because of their large range, numbers and density, distribution arrangements difficult to compare, but they clearly prefer higher latitude and coastal areas over pelagic environments.
This systematic review shows the highest density of killer whales (> 0.40 pieces per 100 km ²) in the northeast Atlantic around the Norwegian coast, in the north Pacific along the Aleutian Islands, the Gulf of Alaska and in the Southern Ocean off the coast of Antarctica lot.
They are considered "common" (from 0.20 to 0.40 individuals per 100 km ²) in the eastern Pacific along the coast of British Columbia, Washington and Oregon, in the North Atlantic Ocean around Iceland and the Faroe Islands. High density has also been reported but are not counted in the western North Pacific around the Sea of Japan, Sea of Okhotsk, Kuril Islands, Kamchatka and the Commander Islands and in the southern hemisphere off the coast of South Australia, Patagonia, off the coast of southern Brazil and the southern tip of Africa. They are reported as seasonally common in the Canadian Arctic, including Baffin Bay between Greenland and Nunavut, and around Tasmania and Macquarie Island. Information for offshore regions and tropical waters are increasingly rare, but the appearance of the area, if not always, shows the killer whale can survive in most water temperatures. They have been seen, for example, in the Mediterranean, the Arabian Sea, Gulf of Mexico and the Indian Ocean around the Seychelles.
Probably the largest population lives in Antarctic waters, where they range up to the edge of the ice layer and is believed to tour the compact ice, finding open leads like beluga whales in the Arctic. In contrast, killer whales summer seasonal guests to Arctic waters, where they do not approach the ice. With the decline of Arctic sea ice in Hudson Strait fast, their coverage has now spread deep into the northwest Atlantic.
Migration patterns are poorly understood. Each summer, the same individuals appear off the coast of British Columbia and Washington. Despite decades of research, where these animals go for the rest of this year is not yet known. Transient pods have been seen from southern Alaska to central California. Killer whale population is sometimes a visit by 160 km (100 miles) in a day, but can be seen in the general area for a month or more. Killer whale pod ranges vary from 320 residents to 1,300 kilometers (200-810 miles).
Occasionally, killer whales swim into freshwater rivers. They have been documented 100 miles (160 km) along the Columbia River in the United States. They have also been found in the Fraser River in Canada and the Horikawa River in Japan.
Population
Estimated population around the world is uncertain, but recent consensus indicates the absolute minimum of 50.000 local arrangements including about 25,000 in the Antarctic, 8,500 in the tropical Pacific, the sea air off the Pacific from 2.250 to 2.700 and from 500 to 1.500 off . Norway. Japanese Fisheries Office estimated 2,321 killer whales in the seas around Japan.
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