Orca

Orcas are also known as killer whales, this species has a fearsome reputation - with pod members hunting together -but it is not known to attack people. They are expert hunters, being armed with up to 50 large, pointed teeth, and they catch prey in all areas of the ocean. Although orcas have been detected 1 km (0.6 miles) below the surface, they prefer to hunt in shallow coastal waters and often swim into bays and mouths of rivers to snatch food near the shore. Like other members of the dolphin family, killer whales must surface regularly to breathe, although they can remain submerged for 15 minutes at a time.

Orcas have black upper bodies and white undersides. These "whales " are really one of the largest members of the dolphin family.

Orcas typically live in pods of five or six individuals. Generally each pod is run by a large male, although larger groups have several adult males. Females and their young may split off into subgroups. Like other toothed whales and dolphins, orcas produce click sounds that are used for echolocation. The whales also communicate with each other using high-pitched screams and whistles. Many pods roam through the oceans, travelling up to 161 km (160 miles) per day, although some are sedentary, especially in areas where fish are plentiful.

Orcas have several hunting techniques. They break pack ice from beneath, knocking their prey into the water, or they may rush into shallow water to grab prey from the shore. It is reported that they may crash on to the shore to drive prey into the surf, where other members of the pod pick them off. Orcas breed throughout the year, although most mate in the early summer and give birth in the autumn of the following year. Each pod has a single male, which mates with all the adult females.

Distribution: Occurs widely throughout the world’s oceans, often close to the shore, but is most common in temperate and polar regions rather than in tropical waters.

Habitat: Coastal waters.

Weight: 3.6 - 8.2 tonnes (4 - 9 tons); males are much bigger.

Length: 7.0 - 9.8 m (23 - 32 ft).

Maturity: 10-18 years; females tend to mature earlier.

Gestation Period: 400 - 520 days.

Breeding: 1; weaning occurs after 13 - 17 months.

Diet: Feeds mainly on larger vertebrates, including sea lions, penguins, sharks and porpoises; also hunts squid.

Lifespan: Can be over 80 years.

Status: Lower risk.

Dorsal fin

Can be up to 1.8 m (6 ft) long. It is triangular in male orcas, shorter and curved in females and young of both sexes.

Patterning

Markings are consistent but sufficiently individual to allow separate members of a pod to be easily recognized.

Flippers

The flippers are broad, measuring up to 0.91 m (3 ft) in width and 1.8 m (6 ft) long. They have rounded tips.

GROUP HUNTING

Killer whales are called "wolves of the sea", because of the way they hunt as a pack, surrounding their prey.

Gallery of Orca