Why do captured orcas kill people

Everything for entertainment: the ordeal of trapped orcas

Another ten orcas that have been caught in the sea are currently suffering in small sea basins on Russia's east coast while the government investigates their possibly illegal catch. If the animals end up being sold - likely to Chinese aquariums - the number of captive orcas could rise to 69.

There is ample evidence that whales - from small dolphins to larger species - do not live well in captivity. The highly intelligent and social animals are evolutionarily designed to cover great distances in the sea. Orcas, whether captured or born in captivity, suffer the most, as Naomi Rose says. The marine mammal scientist works for the non-profit Animal Welfare Institute.

Part of that is due to their sheer size. The massive animals cover long distances in the wild, an average of 65 kilometers a day. They don't just do it because they can, but because they have to - to find varied food and to keep fit. Every day they dive several times to a depth of 30 to 150 meters.

"That's a fundamental part of their biology," said Rose. An orca born in captivity also has the same natural needs. "If you've evolved to travel great distances in search of food and mate, then you're designed for that kind of movement, whether you're a polar bear, an elephant, or an orca," said Rose. "If you put [orcas] in a tank that is 45 x 28 x 9 meters, you basically turn them into couch potatoes."