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Home / News / General / Hawaii’s cetaceans

Hawaii’s cetaceans

By: Denver Leaman

Killer Whale



Killer Whale (Orcinus orca)
Suborder: Odonticeti Family: Delphinidae
Has been sighted in Hawaiian waters. Actually a dolphin.

Other known names:

Orca, Grampus

Identity Keys to use in the field:

Robust body, Single blowhole, Large paddle-like flippers, Black and white in color, White chin, Grey saddle-patch, Tall dorsal fin, White patch behind eyes, Fast active swimmer

General description and habits:

Killer whales are large, stocky, and heavy! Their jet black, white and gray markings, and the males' very tall dorsal fin, make them hard to muddle up with other species. In fact, a male's dorsal fin can be as tall as a man, up to 1.8m (6ft) high. It is the tallest dorsal fin in the animal kingdom. Females have a much smaller fin; theirs is only about half the size and is more curved. Young calves can be a little trickier to identify as their saddle-patch (the patch behind the dorsal fin) can be quite dark and therefore blend into the rest of their bodies; and their light patches (behind the eyes and on the belly) can look a bit pink or rusty colored. Researchers use the dorsal fins to identify individual Orcas. Different shapes, sizes, nicks and scars help them remember which whale is which. Saddle-patches are also unique to individual whales; no two Orcas have exactly the same saddle-patch shape and pattern. Different Orcas populations vary slightly from one another. For example, those living in the Antarctic are smaller and their patches more yellowy then those in the north, and those off Australia and New Zealand are dark purplish-brown with ivory colored patches. Orcas have between 20 and 26 large sharp teeth in both upper and lower jaws; these curve backwards towards the throat and interlock when the whale closes its mouth. They are perfectly designed for catching and biting their food. Orcas are the largest of all the members of the dolphin family. Adults can range from approximately 5.5 to 9.8 meters (18 - 32.25 ft). Males are larger then females, they average 7 - 8 meters, females around 6 meters. Newborn Orcas are usually 2.1 to 2.5 meters (7 - 8.25 ft) long. Adults weigh anything from 2.6 to 9 tonnes (males are generally heavier then females) and newborns are approximately 180 kg (395lb). Studies in northwest North America suggest that there are three kinds of Orcas (resident, transient and offshore), although Orcas from other parts of the world don't always fit neatly into one of these categories. Residents tend to form large family groups or pods (usually 5-25 animals). They have relatively small home ranges (particularly in the summer) and feed mainly on salmon and other fish. They normally hunt using echolocation. Residents also 'talk' to one another more often than other Orcas. They are the most studied of all the Orcas, because they have predictable eating habits and are therefore relatively easy for scientists to find and follow. Transients tend to form smaller family groups or pods (usually 1-7 animals). They tend to roam over a much wider area and feed on seals, sea lions, dolphins and other mammals, as well as seabirds and a variety of other wildlife. They do not hunt using echolocation, probably because their prey have good hearing and would be able to hear the Orcas' clicking sounds. Instead they swim quietly, listening to sounds being made by other animals in the water. Transients 'talk' to one another less often then resident Orcas and have slightly more pointed dorsal fins. Offshores were only identified for the first time in the early 1990s. They appear to travel in large groups of 25 or more. Most of their time is spent in the open sea, much further away from shore then either residents or transients. They probably eat mainly fish and make lots of noise, communicating with each other regularly. Orcas can be very acrobatic. They are known to breach, lobtail, flipper-slap and spy-hop.

Diet:

Fish, Squid, Seabirds, Turtles, Sea lions, Seals, Other cetaceans

Distribution:

Orcas are among the most widely distributed mammals on Earth. In many areas they are not particularly common, but they are found in all the oceans of the world. Some of the best places to see them are: Vancouver Island, Canada; the San Juan Islands, USA; and Tysfjord, in northern Norway. They tend to be more common in cold waters (such as the Arctic and Antarctic) than in warm waters and generally prefer deep water, although they are quite often seen in shallow bays and estuaries.

Population estimates:

Although the number of whales in particular populations may be known, the worldwide population size of Orcas is not.

Threats:

Boat traffic, Hunting/Whaling, Habitat loss, Noise pollution, Prey depletion (lack of food), Captivity industry

Interesting facts:

Orcas are one of the fastest animals in the sea. They can travel almost as fast as a galloping racehorse! The record holder is a male timed at 34.5 miles per hour in 1958. Orcas have been known to feed on over 25 different species of whales and dolphins, including some that are very big (sperm whales, gray whales and blue whales). Not all Orcas eat other mammals though. The resident population off Vancouver Island, for example, eats fish. Their favorite food is salmon. Male Orcas generally don't live as long as females. In the wild, males average 35 years or so, maximum 50-60 years, females average 50 years, maximum 80-90 years. However, one male, known as 'Old Tom' was reportedly spotted every winter between 1843 and 1932 off New South Wales, Australia. This would have made him at least 89 years old. Once in captivity, the lifespan is drastically reduced to an average of only 5 or 6 years. Orcas belong to a group of cetaceans known as the 'blackfish', all of which are actually dolphins. This group also contains pilot whales and melon-headed whales. A typical Orca will eat about 5% of its body weight a day. This means that a large male needs to eat about 400kg of food.

pagelinks.tpl
Hawaii’s cetaceans
  • Humpback whales
  • Striped Dolphin
  • Spinner Dolphin
  • Baird’s Beaked Whale
  • Pacific Bottlenose Dolphin
  • Blainville's Beaked Whale
  • Bryde's Whale
  • Cuvier's Beaked Whale
  • Dwarf Sperm Whale
  • False Killer Whale
  • Fin Whale
  • Killer Whale
  • Melon-headed Whale
  • Minke Whale
  • Northern Right Whale
  • Pygmy Killer Whale
  • Pygmy Sperm Whale
  • Risso's Dolphin
  • Rough-toothed Dolphin
  • Short-finned Pilot Whale
  • Sperm Whale
  • Spotted Dolphin

     

     

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