THE “Declaration of the Rights of Man” was a crucial step in the French revolution. The document, drafted by the Marquis de Lafayette, marked a break with the political past by proposing that everyone, however humble his birth, had certain inalienable civil rights. These were liberty, property, security and resistance to oppression. Merely being a man conferred them.

These days, such rights extend to women as well. But what if you are not human? A session on cetaceans at the AAAS meeting discussed a proposal that whales and dolphins, too, should have rights. The suggestion of the speakers was that the protections these species are afforded by human laws should be extended and recognised not as an indulgence of the human aristocracy towards the bestial peasantry, but as a right as natural as those which humans now afford, in the more civilised parts of the world, to themselves.

The proposition that whales have rights is founded on the idea that they have a high degree of intelligence, and also have self-awareness of the sort that humans do. That is a controversial suggestion, but there is evidence to support it. Lori Marino of Emory University, in Atlanta, Georgia, reviewed this evidence.

One pertinent observation is that dolphins, whales and their kind have brains as anatomically complex as those of humans, and that these brains contain a particular type of nerve cell, known as a spindle cell, that in humans is associated with higher cognitive functions such as abstract reasoning. Cetacean brains are also, scaled appropriately for body size, almost as big as those of humans and significantly bigger than those of great apes, which are usually thought of as humanity's closest intellectual cousins.

Whales and dolphins have complex cultures, too, which vary from group to group within a species. The way they hunt, the repertoire of vocal signals and even their use of tools differs from pod to pod. They also seem to have an awareness of themselves as individuals. At least some can, for example, recognise themselves in a mirror—a trick that humans, great apes and elephants can manage, but most other species cannot.

Thomas White, of Loyola Marymount University, in Los Angeles, then discussed the ethical implications of what Dr Marino had said. Dr White is a philosopher, and he sought to establish the idea that a person need not be human. In philosophy, he told the meeting, a person is a being with special characteristics who deserves special treatment as a result of those characteristics. In principle, other species can qualify. For the reasons outlined by Dr Marino, he claimed, cetaceans do indeed count as persons and therefore have moral rights—though ones appropriate to their species, which may therefore differ from those that would be accorded a human (for example, the right not to be removed from their natural environment).

Chris Butler-Stroud, of the Whale and Dolphin Conservation Society, in Britain, and Kari Koski of the Whale Museum in San Juan Island, Washington state, then charted some of the hesitant steps already being taken in the direction of establishing cetacean rights. Mr Butler-Stroud showed how the language used by international bodies concerned with these animals is changing. The term “stocks”, for example, with its implication that whales and dolphins are a resource suitable for exploitation, is being overtaken by “populations”, a word that is also applied to people.

Ms Koski gave an even more intriguing example. She told of how a group of killer whales that lives near Vancouver, passing between waters controlled (from a human point of view) by Canada and the United States, have acquired legal protection even though the species as a whole is not endangered. After a battle in the American courts these particular whales have been defined by their culture, and that culture is deemed endangered.

The idea of rights for whales is certainly a provocative one, and is reminiscent of the Australian philosopher Peter Singer's proposal that human rights be extended to the great apes—chimpanzees, bonobos, gorillas and orang-utans. Like Dr Singer's suggestion, though, it does ignore one nagging technicality. The full title of the French revolutionary document was “Declaration of the Rights of Man and Citizen”. No one has yet argued for votes for whales and dolphins. But considering some of the politicians who manage to get themselves chosen by human electorates, maybe it would not be such a bad idea.