Status: Deficient Data
Known as: Killer Whale, Orca, Orca Whale, Blackfish.
Estimated numbers left in the wild: At least 50,000, probably quite a bit higher.
Description: Killer whales, which are actually a species of highly predatory dolphins, weigh up to 5,400 kilograms and can measure up to 9.7 meters long. These sea-dwelling mammals are very distinctive looking and magnificent creatures, with their powerful but streamlined bodies, crisp black and white coloration, and prominent dorsal fin. Killer whales are strong and aggressive apex predators, hunting the seas in large groups or “pods”, and mostly immune from predation.
Orcas, as they are also known, are social animals, and may form pods of up to 40. They are intelligent creatures with large brains, and cooperate in their hunting, somewhat like wolves or other canine species on land. Different pods seem to adopt different “tactics” or “cultures” depending on their prey. Those pods that specialize in hunting fish tend to live in one place for long periods, while those that prey on seals or other larger prey move from one place to another in search of their quarry, and have no fixed abode. Killer whales sometimes travel up to a hundred or so kilometres up a freshwater river in search of fish. They are highly efficient carnivores whose 10-centimetre teeth make short work of sea-birds, seals, fish, squid, and other marine animals. An adult killer whale needs around 225 kilograms of food daily to remain healthy.
Killer whales occasionally take large whales also. They cannot kill blue whales or adult male sperm whales, but can kill calves by exhausting and drowning them, and sometimes adult females, also. Being up on a beach does not protect seals from orcas, since killer whales will haul themselves out a short distance on land to seize prey. Killer whales are highly intelligent and can devise unique methods of catching prey in special circumstances, which other orcas can then learn through observation.
Killer whales have a large, extended social life. Beyond the pod, there are “clans” made up of several loosely allied pods, and communities that are composed of several clans. Mating usually occurs outside the pod but within the clan or community. Orcas are usually born in winter, and if they survive their first few months (which only half of young killer whales do), they may live as much as 90 years, though most do not survive beyond their forties or fifties.
Location: Killer whales are found in every ocean and sea of the world, with the exception of a few inland seas such as the Dead Sea and the Aral Sea. They are most common at high latitudes, where there is abundant prey, and prefer coastal waters, sometimes even entering rivers and travelling far upstream. They are also sometimes found in the deep ocean.
Threats: Killer whales are threatened in a number of ways by human activities. They are vulnerable to chemical absorption, as PCBs and pesticides are absorbed by their prey and concentrated in the orcas’ bodies when they eat other animals. Human competition for food resources – including fish such as salmon – also menaces the species, as the steady emptying of the oceans creates a possibility of lessened food resources for these large, hungry predators.
One unusual source of danger to killer whales comes from sonar, which causes disorientation, beaching, and even outright death from as far as a dozen kilometres away or more. Oil spills and boat collisions are other sources of potentially lethal damage to these beautiful, powerful animals.
Conservation efforts: Many environmental organizations, including Greenpeace and Environmental Defense, have launched major lawsuits in efforts to protect orcas from harmful human activities. Specific populations have been classified as endangered and offered official protection on that basis, though this has often been too little, too late to save the clan or community.
Killer Whale Videos
The Hebridean Whale & Dolphin Trust monitors marine mammals and their habitats off the coast of Scotland. They work to protect various species through outreach and educational programmes.