Perhaps this suit sounds like prime fodder for the Colbert Report (and, alas, it has been). But in fact it raises a profoundly important question, one that several decades of animal rights activism and scholarship have prepared us to explore: Does a non-human animal with obvious intelligence, emotional capacity, social skills, and personal interests warrant protection under the U.S. Constitution?

Critics will instinctively dismiss such a possibility as frivolous, if not a crass publicity stunt. And it's true that PETA has done itself no favors in the past by resorting to sensational tactics to achieve noble goals. But to reject this case because you happen to find PETA offensive would be to ignore the compelling factors surrounding it.

The first is that some exceptionally learned legal minds have spoken in support of animal rights. Consider the opinion of Lawrence Tribe, Harvard Law Professor and renowned constitutional scholar. Speaking directly about the PETA suit, he explained to Bruce Friedrich, for a story in the Georgetown Law Weekly: "It seems to me no abuse of the Constitution to invoke [the Thirteenth Amendment] on behalf of non-human animals cruelly confined for purposes of involuntary servitude." He added, "people may well look back on this lawsuit and see in it a perceptive glimpse into a future of greater compassion for species other than our own."

Next, there are the scientists. Experts claim that orcas are among the most intelligent species on Earth. Naomi Rose, a marine mammal biologist with the Humane Society of the United States, cites research suggesting that whales, dolphins, and porpoises have the cognitive sophistication of 3- to 4-year-old humans. A neuroscientist who measures encephalization quotients -- brain to body size ratio -- of mammals, ranks orcas between great apes and humans. The cortex of an orca has been shown to be more complex than the human cortex. Orcas form complex societies, teach their young, and communicate through a beautifully intricate series of clicks, whistles, and pulsed calls. They undoubtedly experience emotions, including suffering.

But still, many will object, they are not human. Unless you are a Biblical fundamentalist or radical Aristotelean, this is an illogical way to end the argument. The field of evolutionary biology directly undermines the assumption that there's something fundamentally different -- at least in terms of consciousness -- between human and non-human animals.

Darwin himself recognized that the differences between humans and non-humans were "of degree, not kind." Jane Goodall claims that "there is no sharp line between the human animal and the rest of the animal kingdom -- it is a blurred line." Richard Dawkins, the most famous living evolutionary biologist, denounces the failure to appreciate this biological continuum as "human speciesist vanity." We simply cannot rest our case against animals on an idea that completely ignores one of the most basic findings of evolution.