Killer Whale (Orca) Facts

Scientific Name: Orcinus orca

Underwater view of a female orca splashing through the water after it has gone up to breath, Pacific Ocean, New Zealand

 

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With their striking black and white markings and prevalence at marine parks, the killer whale, also known as the orca or Orcinus orca, is probably one of the most easily-recognized cetacean species. The largest of the dolphin species, orcas live in oceans and seas around the world and can grow to 32 feet long and weigh up to six tons. The name killer whale originated with whalers, who called the species "whale killer" because of its tendency to prey on whales along with other species such as pinnipeds and fish. Over time, perhaps because of the whale's tenacity and ferocity in hunting, the name was switched to "killer whale."

Fast Facts: Killer Whales (Orcas)

  • Scientific Name: Orcinus orca
  • Common Name(s): Killer whale, orca, blackfish, grampus
  • Basic Animal Group: Mammal  
  • Size:16–26 feet
  • Weight: 3–6 tons
  • Lifespan: 29–60 years
  • Diet: Carnivore
  • Habitat: All oceans and most seas with a preference for northern latitudes
  • Population: 50,000
  • Conservation Status: Data Deficient


Description

Killer whales, or orcas, are the largest member of the Delphinidae—the family of cetaceans known as the dolphins. Dolphins are a type of toothed whale, and members of the Delphinidae family share several characteristics—they have cone-shaped teeth, streamlined bodies, a pronounced "beak" (which is less pronounced in orcas), and one blowhole, rather than the two blowholes found in baleen whales.

Male killer whales can grow to a maximum length of 32 feet, while females can grow to 27 feet in length. Males weigh up to six tons while females can weigh as little as three tons. An identifying characteristic of killer whales is their tall, dark dorsal fin, which is much larger in males—a male's dorsal fin can reach a height of six feet, while a female's dorsal fin can reach a maximum height of about three feet. Males also have larger pectoral fins and tail flukes.

All killer whales have teeth on both their top and bottom jaws—48 to 52 teeth in total. These teeth can be up to 4 inches long. Although toothed whales have teeth, they don't chew their food—they use their teeth for capturing and tearing food. Young killers whales get their first teeth at 2 to 4 months of age.

Researchers identify individual killer whales by the size and shape of their dorsal fins, the shape of the saddle-shaped, light patch behind the dorsal fin, and scars or marks on their dorsal fins or bodies. Identifying and cataloging whales based on natural markings and characteristics is a type of research called photo-identification. Photo-identification allows researchers to learn about the life histories, distribution, and behavior of individual whales, and more about species behavior and abundance as a whole. 

Back of an orca, showing the dorsal fin and saddle marking that can be used to identify individuals
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Habitat and Range

Killer whales are often described as the most cosmopolitan of all cetaceans. They can be found in all oceans of the world, and not just in the open ocean—near shore, at the entrance to rivers, in semi-enclosed seas, near the equator, and in polar regions covered with ice. In the United States, orcas are most commonly found in the Pacific Northwest and Alaska.

Diet

Killer whales are at the top of the food chain and have very diverse diets, feasting on fish, penguins, and 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.

Killer whale (Orcinus orca) with juvenile Southern sea lion (Otaria flavescens) in mouth, Patagonia, Argentina, Atlantic Ocean
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Behavior

Killer whales may work in pods to hunt their prey and have a number of interesting techniques to hunt prey, which includes working together to create waves to wash seals off ice floes and sliding onto beaches to capture prey.

Killer whales use a variety of sounds for communicating, socializing and finding prey. These sounds include clicks, pulsed calls, and whistles. Their sounds are in the range of 0.1 kHz to about 40 kHz. Clicks are primarily used for echolocation, although they may also be used for communication. The pulsed calls of killer whales sound like squeaks and squawks and appear to be used for communication and socialization. They can produce sounds very rapidly—at a rate of up to 5,000 clicks per second. You can hear killer whale calls here on the Discovery of Sound in the Sea website.

Different populations of killer whales make different vocalizations, and different pods within these populations may even have their own ​dialect. Some researchers can distinguish individual pods, and even matrilines (the line of relationship that can be traced from one mother to her offspring), just by their ​calls.

Group of orcas, Frederick Sound, Alaska, USA
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Reproduction and Offspring

Killer whales reproduce slowly: Mothers give birth to a single baby about every three to 10 years, and pregnancy lasts for 17 months. Babies nurse for up to two years. Adult orcas generally help mothers to care for their young. While young orcas may separate from their birth pod as adults, many stay with the same pod throughout their lives.

Male and female orcas
Male and female orcas. Kerstin Meyer / Getty Images

Threats

Orcas, like other cetaceans, are threatened by a range of human activities including noise, hunting, and habitat disturbance. Other threats faced by killer whales include pollution (orcas can carry chemicals such as PCBs, DDTs and flame retardants that can affect the immune and reproductive systems), ship strikes, reduction of prey due to overfishing, and loss of habitat, entanglement, ship strikes, irresponsible whale watching, and noise in the habitat, which can affect the ability to communicate and find prey.

Conservation Status

The International Union for Conservation of Nature had, for years, described orcas a "conservation dependent." They changed that assessment to "data deficient" in 2008 to recognize the probability that different species of killer whales experience different levels of threat.

Species

Killer whales were long considered one species—Orcinus orca, but now it appears that there are several species (or at least, subspecies—researchers are still figuring this out) of orcas. As researchers learn more about orcas, they have proposed separating the whales into different species or subspecies based on genetics, diet, size, vocalizations, location and physical appearance.

In the Southern Hemisphere, proposed species include those referred to as Type A (Antarctic), large type B (pack ice killer whale), small Type B (Gerlache killer whale), Type C (Ross Sea killer whale), and Type D (Subantarctic killer whale). In the Northern Hemisphere, proposed types include resident killer whales, Bigg's (transient) killer whales, offshore killer whales, and Type 1 and 2 Eastern North Atlantic killer whales

Determining species of killer whales is important not only in gaining information about the whales but in protecting them—it is difficult to determine the abundance of killer whales without even knowing how many species there are.

Killer Whales and Humans

According to Whale and Dolphin Conservation, there were 45 killer whales in captivity as of April 2013. Due to protection in the U.S. and restrictions on trade, most parks now obtain their killer whales from captive breeding programs. This practice has even been controversial enough that SeaWorld stated in 2016 that it would stop breeding orcas. While the viewing of captive orcas has likely inspired thousands of budding marine biologists and helped scientists learn more about the species, it is a controversial practice due to the potential effects on the whales' health and ability to socialize naturally.

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