You eat what you think you're not

Interesting conversation around the lunch table at work last week occasioned by an awareness of rising world food prices. Half of the team are vegetarian, half not. We discussed the aesthetics of eating insects (I discovered the Japanese sometimes eat both bees and grasshoppers), and the ethics of cannibalism.

I'd be prepared to bet a considerable sum of money that you're not a cannibal (if I'm wrong, you can claim your money, but be prepared for me to go to the police) and slightly less money that, if you're a vegetarian, you feel less bad about eating fish than about eating animals, and that your objections to eating insects would be more aesthetic and health-related than moral. There seems to be a principle at work here: the closer an organism is to us on the tree of life, the more uneasy we feel about eating it.

The operation of this principle is slightly obscured by the fact that, in the west at least, the animals that it's culturally acceptable for us to eat are not the closest ones to us on the tree. Most people eat cows, pigs, sheep and chickens without worrying too much, though they wouldn't like to have to kill them in person, and generally prefer not to see their corpses in undismembered form. In the UK at least, we don't generally eat horses; they're considered more intelligent than cows, sheep and pigs. And we certainly wouldn't eat cats and dogs unless the supermarket supply chains were very severely disrupted, because they share our lives and we relate to them as one sentient being to another. In different cultures, the line is drawn in different places. We Brits look down on the French for eating horse meat, but the Japanese are horrified that we eat rabbits.

But even if you feel OK about eating all the above, how would you feel about lemurs? Baboons? Gibbons? Gorillas, even if they weren't threatened with extinction? Chimpanzees? Neanderthals, if there still were any around? Somewhere in that sequence, I bet you will have said: no, that is not for me. At some point, the unease due to a feeling of similarity overrides hunger.

We have to draw the line somewhere, and it'll always be arbitrary to some degree; all life is related, and all life has to eat. But maybe this perspective can provoke a reconsideration of why we draw our personal line where we do, and whether it makes sense to move it. For myself, I know that it was no coincidence that I became vegetarian (except for the occasional relapse when confronted by spaghetti carbonara) during the period of my life I was working intensively with the amazingly similar DNA sequences of superficially very different species, several of whose phenotypes were regularly on offer in the campus restaurant.