- 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.
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Killer whales, which are actually 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 are also known as social animals and may form pods of up to 40. They are intelligent creatures with large brains and cooperate in 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 specializing 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 kilometers up a freshwater river searching for fish. They are highly efficient carnivores whose 10-centimeter teeth make short 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.
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 brilliant 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 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 the young killer whales do), they may live as much as 90 years, though most do not survive beyond their forties or fifties.
See Related: Whale Shark
Killer whales are found in every ocean and sea of the world, except 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 traveling far upstream. They are also sometimes found in the deep ocean.
See Related: Environmental Organizations in South America
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 kilometers away or more. Oil spills and boat collisions are other sources of potentially lethal damage to these beautiful, powerful animals.
See Related: Endangered Species in California
Many environmental organizations, including Greenpeace and Environmental Defense, have launched major lawsuits 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.
See Related: How Do Sharks Help Ecosystems
Hebridean Whale & Dolphin Trust
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 programs.