Orca

Orca (Orcinus orca)
commonly known as Killer Whale
Species Code: OROR

Description: The orca (killer whale) is a toothed whale and is the largest member of the Dolphin family. These large marine mammals are easily distinguished by their black-and-white coloration, large dorsal fin and a sleek, streamlined body. The dorsal surface and pectoral flippers are black except for a grayish patch (saddle) that lies behind the dorsal fin and a white eyespot located just above and slightly behind each eye. The ventral surface, lower jaw and undersides of the flukes are predominately bright white. The distinctive patterns are a form of camouflage to hide their presence when in search of food.

In mature males, the dorsal fin is tall and triangular and can reach a height of 1.8 m (6 ft.). Averages 5.8-6.7 m (19-22 ft.); largest males on record were 9.8 m (32 ft.)

In most females, the dorsal fin is typically smaller and slightly falcate (curved back), reaching an average height of 0.9-1.2 m (3-4 ft.). Length: Averages 4.9-5.8 m (16-19 ft.) Females are generally smaller than males.

Size: 7 to 9.7 m (23 to 32 ft) - about as long as a small bus
Weight: up to 5,443 kg (6 tons)

Range/Habitat:
Orcas are found in oceans worldwide. They are most abundant in the Arctic and Antarctic and in areas of cold-water upwelling.

Live in coastal and offshore waters; resident pods may frequent localized waterways (bays, sounds, etc.) whereas transient pods tend to cover more extensive, varied areas.

An extended clan of orcas, known as the Southern Resident Orca community, socialize and forage in the inland waters of Washington State and British Columbia. Both male and female offspring remain with their mothers their entire lives (Orca Network).

Diet: Orcas are carnivorous (meat-eating) predators. They primarily prey upon marine mammals such as seals, sea lions, and even whales - using their sharp teeth that can be four inches (ten centimeters) long. They are known to grab seals right off the ice. They also eat seabirds, fish, and squid.

The orcas in the Puget Sound are know as fish-eating "resident" killer whales, while those in the open ocean are called mammal-eating "transient" killer whales.

An adult orca consumes 100-300 pounds of food a day, depending on the animals size and energy needs.

Behavior: Like all dolphins, orcas use sophisticated biological sonar, called echolocation. Echolocation enables them to locate and discriminate objects underwater.

The vocalizations within a whale community are distinct and different from those in other communities, serving to keep the pods together. The calls also bring the pods together over large expanses of water when it is impossible for the whales to see each other.

How do Whales Swim?

Their large bodies are streamlined (hydrodynamic), like a submarine, for moving through the water. Whales have flukes or a tail used for swimming. The flukes are moved in an up-and-down motion to accelerate.

The dorsal fin acts like the keel of a boat; it keeps the whale from rolling side to side while swimming.

Whales have pectoral flippers just behind the head. These pectoral flippers are used for steering, turning, and stopping.

How do Whales Breathe?

Whales have lungs they use to get the oxygen they need by breathing air (like humans). But instead of breathing through their mouth, they breathe through their nostrils, called blowholes, located on top of their heads. They can easily breathe through the blowhole without lifting their entire head out of the water.

Reproduction:

Females (cows) reach reproductive maturity at about 14 to 15 years.

Females give birth every three to ten years, following a 17-month pregnancy. Young are able to swim and dive at birth, and they grow quickly on their mothers' milk. Calves are weaned after 12 months. Newborn calves are 7-8 feet long and weigh 136-181 kg (300-400 lb.)

Lifespan:

Some males have been known to live into their 40s and perhaps up to 50+ years old. Females have been known to live to 60+ years old.

Did you know?

• Whales are warm-blooded like other mammals.
• A fatty tissue called "blubber" keeps them warm.
• Echolocation enables them to locate and discriminate objects.
• Orcas live in small, close-knit, groups called pods.
• Males usually live into their 40s and females into their 60s.
• Orcas have no predators.

Two mammal-eating "transient" killer whales photographed off the south side
of Unimak Island, eastern Aleutian Islands, Alaska.
photo by Robert Pittman, NOAA

More information:
Killer Whale - Animal Diversity Web
Killer Whale Facts and Photos - whale-images.com
Killer Whale Facts - National Geographic
The Center for Whale Research
The Whale Museum in Friday Harbor, Washington
Orca Network
Meet the Orcas of the Salish Sea
Gentle Giants of the Salish Sea - interactive curriculum

   
Photos: Killer Whale Photos - Center for Whale Research
Audio: Orca Audio - Center for Whale Research
Photo credits: Natures Pics (Harbor seal), Tim Knight, Robert Pittman