The animals have distinctive cultures, societies and personalities and are so complex that they should be considered in the same light as people, experts said.
Isolating dolphins and orcas in tanks at amusement parks is morally wrong because the animals are even more socially driven than humans, they added, while killing them is tantamount to murder.
The marine experts hope to persuade international authorities to enshrine in law the rights of cetaceans, a group of water-dwelling mammals which also includes porpoises.
Discussing their “declaration of rights” for cetaceans at the American Association for the Advancement of Science (AAAS) annual meeting in Vancouver, an international team of researchers said the animals should have the same rights to life, liberty and wellbeing as humans.
Dr Thomas White, an ethics expert at Loyola Marymount University in California, said: “The similarities between cetaceans and humans are such that they, as we, have an individual sense of self.
“Dolphins are non human persons. A person needs to be an individual. If individuals count, then the deliberate killing of individuals of this sort is ethically the equivalent of deliberately killing a human being.
“The science has shown that individuality, consciousness, self awareness is no longer a unique human property. That poses all kinds of challenges.”
Recognising the status of cetaceans in law is important because it would make commercial whaling and imprecise fishing methods which kill hundreds of thousands of dolphins and whales each year morally abhorrent, he said.
Recent scientific studies on dolphins’ brains have shown they are more intelligent than chimpanzees, and they communicate with each other in a similar way to humans.
They are also able to recognise themselves in a mirror, to learn and teach one another new types of behaviour, and are capable of thinking about the future, research shows.
An experiment at the Institute for Marine Mammal Studies in Mississippi in which dolphins were rewarded for clearing rubbish from their enclosures highlighted their remarkable intellectual capabilities.
One dolphin named Kelly began hiding large paper bags at the bottom of her tank, ripping them apart and bringing them to her handler one at a time to trick him into giving her multiple rewards.
A group of researchers established the Declaration of Rights for Cetaceans at a conference in Helsinki two years ago, and is now canvassing support from scientists in the hope of bringing it to the attention of policymakers.
The ten-point document says each individual cetacean has the right to life, to a free existence in their natural habitat and to the protection of their environment.
It adds that no person or organisation has the right to own a cetacean, or to disrupt their culture.
Cetaceans are entitled to have these rights set down in an internationally recognised legal document, it concludes.
Read full article By Nick Collins, The Telegraph