Boundaries of Vegetarianism


I am interested in what animal species vegetarians are or are not ethically allowed to consume or damage.

I assume that protozoans are acceptable for use,

but what of sea sponges?
or corals?
or jellyfish?

What attribute of the animal kingdom defines the boundary of acceptability for consumption?

The non-existence of a solid cell wall?
or the presence of the nerve cell?


Be aware that people are vegetarians for many different reasons, and resolve difficult questions in different ways. For instance, someone who simply doesn’t like meat, might try sea-food and see if they like that. Somone who’s vegetarian for religious reasons will hopefully have a helpful list of rules somewhere.

I’m assuming you’re really interested in people who are vegetarians for ethical reasons. But still, everyone does it differently. Some people’s line is ‘has a face’ which I think is a bit shallow, but I can’t really criticise. I go for ‘well, technically, anything with a reasonable nervous system, but since I don’t want to eat little slimy things anyway, it’s a bit moot’. Some people go to extremes and rule out anything which would be killed by eating it. At this point we move to IMHO.

This is discussed a lot - you should try searching the archives, and googling.

My boundary is the kingdom Animalia. Plantae and Fungi are in, Animalia is out. As for Protista, they’re so tiny that to deliberately exclude or include them is irrelevant. Monera includes blue-green algae, doesn’t it? Spirulina is definitely in.