Marine Biology

An Introduction to Killer Whales



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Killer whales, also known as the orcas, are the top predators in the marine food chain.  Despite its name, the killer whale is actually a dolphin instead of a true whale.  Like most dolphin species, killer whales belong to the delphinidae family.  The scientific name for killer whales is orcinus orca.  They belong to the order cetecea, which includes both dolphins and whales.

Appearance:

Killer whales, or orcas, have a distinct black and white coloration.  The bottom of the jaw is white while the top is black, except for a semi-oval shaped white marking above the eye.

Killer whales have tall dorsal fins that can reach up to 1.7 m (6.8 inches) in height in adult males.  Male killer whales can reach up to 9 m (30 feet) in length and weigh as much as 8100 kg (9 tons).  Females are somewhat smaller than males.

Behavior:

Killer whales generally live in pods of between 2 and 8 animals.  Pods can grow, however, to include as many as 30 to 40 animals.  Killer whales’ feed mainly on fish and squid.  They have also been known to feed on penguins, seals, other species of dolphins, whales and almost all other marine mammals.  They often hunt cooperatively, in packs.  This allows them to attack prey that is much larger than they are.  Packs of killer whales, for example, are one of the few predators known to attack adult blue whales (Balaenoptera musculus), the largest mammal on the world (1).

Adult killer whales are apex predators who face no threats from any other animals, not even large shark species.  Killer whales can reach speeds of up to 35 mph in the water.  They can leap far above the surface.

The young are born in winter, after a gestation period of perhaps 16 months.

Distribution:

Killer whales occupy all the oceans of the world.  They tend to prefer coastal areas, however, and are less common in the open ocean.  Killer whales tend to be most common in Arctic and Antarctic waters.

Killer whales can sometimes be seen off some parts of the Pacific coast North America.  They are a popular species for whale-watchers in the Canadian province of British Columbia.

Killer Whales in Popular Culture:

Killer whales are intelligent and easy to train.  This is why they have become a mainstay at aquariums, marine parks and circuses around the world.  In marine land, for example, trained killer whales jump through hoops on command for the enjoyment of audiences.  Trained killer whales have played roles in films and on television, most notably in the 1993 hit children’s movie “Free Willy” (2).

In the wild killer whales are top predators that feed on most other marine mammals as well as fish and other marine creatures.  Many people, however, are most familiar with the trained killer whales that perform tricks for people’s amusement.  The apparent harmlessness of the trained killer whales is a far cry from their real role as predatory hunters.

Notes:

1. E.D. Mitchell and R. Reeves, “Cetacea” in The Canadian Encyclopedia.  Edmonton, Alberta.  Huntig Publishers, Ltd., 1988., 390-C.

2. Free Willy was directed by Simon Wincer.  It starred Jason James Richter, Lori Petty, Michael Madsen and others.  Its non-human star was a killer whale.  The plot of this children’s movie revolved around the relationship between a boy (Richter) and an exploited killer whale.  The film became a hit, inspiring two sequels (Free Willy 2: The Adventure Home in 1995 and Free Willy 3: The Rescue in 1997) and an animated television series.

Reference:

E.D. Mitchell and R. Reeves, “Cetacea” in The Canadian Encyclopedia.  Edmonton, Alberta.  Huntig Publishers, Ltd., 1988., 390-B-C-391-A.

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