The animals have different cultures, societies and personalities that are so complex that they should be seen as the same as people, said the experts.
They added that isolating dolphins and orcas in amusement parks is wrong because the animals are even more socially driven than humans and that killing them amounts to murder.
The international team of scientists, philosophers and animal rights groups addressed the American Association for the Advancement of Science (AAAS) in Vancouver to discuss the “declaration of rights” for cetaceans.
Dr Thomas White, 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 cetaceans in law is crucial, he said, because it would make commercial whaling and certain fishing methods that kill hundreds of dolphins and whales a year.
Whale watching trips would be regulated to respect the creatures’ privacy and developers and oil companies would have to consider the effect their projects would have on animals’ life and culture.
Recent studies on dolphins’ brains show that they are more intelligent than chimpanzees and the way they communicate with each other is similar to that of humans.
They can also recognise themselves in mirrors, teach each other new types of behaviour and can think about the future.
Psychologist Dr Lori Marino, from Emory University in Atlanta, said scientific advances had changed how the cetacean brain is understood.
She said: “We went from seeing the dolphin/whale brain as being a giant amorphous blob that doesn’t carry a lot of intelligence and complexity to not only being an enormous brain but an enormous brain with an enormous amount of complexity, and a complexity that rivals our own.
“Its different in the way it’s put together but in terms of the level of complexity its very similar to the human brain.”