ORCA
Classification:
The orca is the apex predator of the sea and the largest member of the dolphin family. It is highly intelligent, highly adaptable and able to communicate and coordinate hunting tactics. Not typically a migratory species, orca ‘migrations' are principally in response to changes in favoured prey abundance and can sometimes be long, e.g between Alaska and California. Depending on the type of social group and location, orcas will hunt fish, squid, seals, sea lions, seabirds and even whales much larger than themselves. There has never been a documented attack on a human in the wild, and there are some stories of orcas actually protecting humans at sea from sharks. The taxonomy of this genus however is clearly in need of review, and it is likely that Orcinus orca will be split into a number of different species or at least subspecies over the next few years.
resident's versus transients.
A resident pod is less aggressive and tends to prefer fish. Transient pods act much like wolf packs and are much more aggressive. They hunt marine mammals by working together.
Appearance:
The orca, also known as a killer whale, is distinctive in appearance with a large black body, a white underside, a white patch above and behind the eye, and a grey 'saddle patch' behind the dorsal fin
At up to nearly 10 metres long, male orcas are larger than females and have a tall dorsal fin - up to nearly 2 metres in height. The tall sword-shaped and strikingly visible dorsal fin makes them almost unmistakable at sea. Female length is about 20% less and the curved dorsal fin is less than half the height of the males. Look out for orcas at OrcaLab in British Columbia (which WDC helps to fund) in the video below. You may also see humpback whales, Dall's porpoises and Pacific white-sided dolphins.
Behaviour:
Orcas are extremely fast swimmers and have been recorded at speeds of up to 54km/h. Most studies have centred around the Pacific Northwest where three distinct ecotypes exist: coastal fish-eaters (‘residents'); marine mammal eaters (‘transients') and ‘offshores' – whose dietary habits are unknown. One striking feature of the ‘resident' orcas in this area is that no apparent dispersal or immigration of birth group has been recorded in 30 years of study, making them one big family group.
A ten-year study in Kamchatka has identified two separate ecotypes of fish-eaters and transients. In Antarctica three ecotypes are recognised with more pronounced morphological and biological differences. Various specialised hunting techniques have been observed. Off Peninsula Valdes, Argentina, and the Crozet Islands, orcas feed on South American sea lions and Southern elephant seals in shallow water, even beaching themselves temporarily. Adult killer whales have been observed to teach the younger ones the skills of hunting in shallow water. Another technique for capturing seals is known as wave-hunting: killer whales spy-hop to locate seals resting on ice floes and then create waves by swimming together in groups. As the water washes over the floe, it makes the seal slide into the water where an orca waits to kill it.
Orcas, or killer whales, are the largest of the dolphins and one of the world's most powerful predators. They feast on marine mammals such as seals, sea lions, and even whales, employing teeth that can be four inches long. They are known to grab seals right off the ice. They also eat fish, squid, and seabirds.
Classification:
The orca is the apex predator of the sea and the largest member of the dolphin family. It is highly intelligent, highly adaptable and able to communicate and coordinate hunting tactics. Not typically a migratory species, orca ‘migrations' are principally in response to changes in favoured prey abundance and can sometimes be long, e.g between Alaska and California. Depending on the type of social group and location, orcas will hunt fish, squid, seals, sea lions, seabirds and even whales much larger than themselves. There has never been a documented attack on a human in the wild, and there are some stories of orcas actually protecting humans at sea from sharks. The taxonomy of this genus however is clearly in need of review, and it is likely that Orcinus orca will be split into a number of different species or at least subspecies over the next few years.
resident's versus transients.
A resident pod is less aggressive and tends to prefer fish. Transient pods act much like wolf packs and are much more aggressive. They hunt marine mammals by working together.
Appearance:
The orca, also known as a killer whale, is distinctive in appearance with a large black body, a white underside, a white patch above and behind the eye, and a grey 'saddle patch' behind the dorsal fin
At up to nearly 10 metres long, male orcas are larger than females and have a tall dorsal fin - up to nearly 2 metres in height. The tall sword-shaped and strikingly visible dorsal fin makes them almost unmistakable at sea. Female length is about 20% less and the curved dorsal fin is less than half the height of the males. Look out for orcas at OrcaLab in British Columbia (which WDC helps to fund) in the video below. You may also see humpback whales, Dall's porpoises and Pacific white-sided dolphins.
Behaviour:
Orcas are extremely fast swimmers and have been recorded at speeds of up to 54km/h. Most studies have centred around the Pacific Northwest where three distinct ecotypes exist: coastal fish-eaters (‘residents'); marine mammal eaters (‘transients') and ‘offshores' – whose dietary habits are unknown. One striking feature of the ‘resident' orcas in this area is that no apparent dispersal or immigration of birth group has been recorded in 30 years of study, making them one big family group.
A ten-year study in Kamchatka has identified two separate ecotypes of fish-eaters and transients. In Antarctica three ecotypes are recognised with more pronounced morphological and biological differences. Various specialised hunting techniques have been observed. Off Peninsula Valdes, Argentina, and the Crozet Islands, orcas feed on South American sea lions and Southern elephant seals in shallow water, even beaching themselves temporarily. Adult killer whales have been observed to teach the younger ones the skills of hunting in shallow water. Another technique for capturing seals is known as wave-hunting: killer whales spy-hop to locate seals resting on ice floes and then create waves by swimming together in groups. As the water washes over the floe, it makes the seal slide into the water where an orca waits to kill it.
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