An orca, or killer whale, far left, slips through the calm waters off northern Vancouver Island, British Columbia. This approachable species has been studied intensively since the early 1970s. Although called killer whale, it is actually the largest dolphin, growing up to 9.8 metres long and weighing as much as 5,000 kilograms. As part of an aquarium show, a young bottlenose dolphin, left, at Sea Life Park in Hawaii, leaps high into the air for a fish reward. The orca and the bottlenose dolphin are the most popular and well-known dolphins. Both species live in every ocean, in inshore as well as offshore waters, and have been frequently kept in aquariums and marine parks. These adaptable animals are capable of a wide range of behaviours. Not simply "warriors of the sea" that eat anything and everything, orcas are at times crafty, opportunistic predators which use highly developed social skills to catch their food. Likewise, bottlenose dolphins, although showing an overriding curiosity about everything in their world, can occasionally be aggressive.
Rauno Lauhakangas