Who or what?
 

We have the answer "Lions eat meat." and we need the subject question.Can we say "Who eats meat?" or the best question is "what eats meat?"??????:doh::

Re: Who or what?
 

This is difficult to answer out of context. Imagining a text which described the habits of three different animals - say, lions, horses and seals and explained that lions eat meat, horses hay and seals fish - then the best question would be Which animal eats meat? or Which of the three animals eats meat?

If the question was general rather than restricted to a limited choice (as above, where I have three possibilities only), then you could say : What animals eat meat? - the answer being lions, tigers, cats, dogs, hamsters and all other carnivores and omnivores.

Who eats meat? would only be used if the lion was being anthropomorphised - ie given human qualities. This might happen in a book for small children : Now at the zoo we can see Larry the lion, Harry the horse and Sallie the seal. One of them eats meat, one eats hay, and one eats fish. Who eats fish?

What eats meat? is very unlikely to be used at all.

Re: Who or what?
 

Susan gives very thoughtful answers! I pretty much agree with everything. I only slightly disagree in one point. "Who" is reserved for people and companies (in American English). "What" is used for things.

Re: Who or what?
 

Yep, I agree with bread_baker's explanation. You only use WHO if you refer to a person or to a known entity.

Re: Who or what?
 

Not sure what Clevermae means by a "known entity" but regarding animals, you'd certainly use "who" if you were talking to your pets.

Who's a pretty boy? (to a budgie)
Who's a good dog?
Who wants to go walkies?
etc

Re: Who or what?
 

I'm American and I'd agree with Sue on this. Once you personify or personalize the animal, I'd use "who".

In Sue's example from before, if no personification were added,
Now at the zoo we can see a lion, a horse and a seal. One of them eats meat, one eats hay, and one eats fish. Which one eats fish?

I'd use "which one", neither "who" nor "what".

Re: Who or what?
 

I meant like an established company, or an institution, or a group. :)