Why this concern for a crustacean? Because scientific evidence indicates that lobsters feel. They have a nervous system and senses, including vision, touch and chemical perception. They approach good things and avoid bad things. They can live a century, they learn and they remember. There is even evidence that they play.
The capacity for feeling both good and bad things - the scholarly term is "sentience" - is central to the ethics of how we treat animals. If you're sentient, you have some quality of life at stake, and you deserve moral consideration.
As a biologist and animal behavior specialist, I know that science has historically shown a profound disinterest in animals' capacity for good feelings. Thankfully, that's now changing, and scarcely a week passes without some new scientific revelation about animal minds, emotions and feelings. Inevitably, these revelations are starting to inform real-world decisions: witness the Whole Foods live lobster sale ban and the recent decision by the Chicago City Council to end the sale of foie gras in the city's restaurants.
What is the evidence, then, that pleasure plays an important role in how animals experience the world? First, there is the simple fact that as humans, we experience pleasure, and this suggests that similar creatures - equipped with nervous and sensory systems - do, too.
There are also parallels between our emotional and biochemical responses and theirs. For example, when rats are anticipating opportunities to play, their brains show an increase in dopamine, a compound associated with pleasure in humans. And goldfish show a clear preference for swimming in places where they have received amphetamine, a drug that stimulates dopamine release from their brains.
Pleasure is also adaptive. Just as evolution favors pain as punishment for dangerous or maladaptive behaviors, pleasure evolved to reward behaviors that encourage survival and procreation. That's why food, sex, play, touch, rest and comfort feel good to us.
But for most of us, it is how animals behave that provides the best window onto their inner lives. If you've been owned by a cat or dog, you have probably witnessed the animal's blissful comportment during a chin scratch or a belly rub - and received a nudge for more when you withdrew your hand.
Nature abounds with pleasure. Picture this: A group of hippopotamuses rests motionless in the cool of an African freshwater spring. Schools of tiny fish have gathered around their flanks and feet, nibbling at parasites and sloughing skin. The spa-going hippos, far from passive participants, splay their toes, gape open their mouths, and spread their legs to assist the fishes in their cleaning services.
Ravens are noted players. They often engage in aerial frolics, slide down snowy banks, and have even been seen playing "rodeo," a game in which the birds perch on a wind-whipped power line, grab another line in their beaks, and try to hold on.
Other manifestations of animal pleasure include exhilaration, joy, love, curiosity and mischief. Humor, too, is not only the province of humans. Chimps mock, dogs tease and parrots provoke. When asked to identify the color of a white towel held up by her teacher, a gorilla named Koko repeatedly signed "red." Then, grinning, she plucked off a bit of red lint clinging to the towel, held it up to the teacher's face, and signed "red" again.
What are the implications for humankind's relationship to animals when we acknowledge and embrace the richness of their sensory experiences? It is sometimes convenient to exclude animals from our sphere of moral concern - as we do, for example, in the making of foie gras or lobster salad or in the meat industry in general. But is it right?
Because animals can enjoy life, our moral obligations to them are greater. We may not have an obligation to provide pleasure to animals, but actively depriving them of the opportunity to fulfill natural pleasures - as we do when we cage or kill them - is another matter. As we awaken to the rich landscapes of animal sentience, it only follows that lobster tanks and foie gras are on their way out.
Jonathan Balcombe is an ethologist and research scientist with the Physicians Committee for Responsible Medicine and the author of "Pleasurable Kingdom: Animals and the Nature of Feeling Good." Readers may write to him at: PCRM, 5100 Wisconsin Avenue NW, Suite 400, Washington, D.C. 20016; Web site: http://www.pcrm.org" Target="_BLANK">http://www.pcrm.org.