Useful Facts about Orcas

The Creatures:

Orcas belong to the sub order of toothed whales and are members of the dolphin family. The average weight of an Orca is around four tonnes and they can reach six to eight metres in length. It is believed that the female killer whale can live up to 80 years old and the males up to 60.

Distribution:

Orcas are the most abundant of whale species and inhabit all the oceans of the world. Their distributino is limited by pack ice and they prefer cooler waters.

Diet:

Orcas are top predators in the ocean. Their food preferences vary according to their locality. In Norwegian waters, herring is the main prey for Killer whales. Other prey includes marine mammals (other whales, seals, sea lions and walruses), fish, squid and occasionally sea birds, sea otters and penguins. A killer whale consumes up to 100 kilos daily.

Sounds:

The Orca dive lasts from one to four minutes. Sound travels faster and further through water than air and in the underwater world where light usually does not penetrate very far from the surface, hearing becomes an important sense. Killer whales, as all other dolphins, rely very much on sounds for communication and for obtaining information about their environment. They produce a variety of vocalisations including calls, whistles and echolocation clicks. Whistles are pure tone sounds used mostly during social events. The calls are made of several short clicks so close together that they appear to be a continuous sound.

Each pod has a repertoire of discrete calls that is unique to the group. Echolocation clicks made by killer whales are rapid signals used for navigation and detection of objects in the whale's surroundings. By producing a click and waiting for a reply, a whale can estimate with amazing accuracy the distance and density of the objact that reflected their echo. This finely tuned system allows the killer whales to find their way and food indpendently of whether it is light or dark.