At least according to this article. I think it needs to be done. And, I'm not talking about whether a chimp, for example, should be declared a "person".
I think that in the wake of the pet food scandal in the US and Canada, there are issues that need to be worked out. Is a companion animal "worth" only the replacement value, or is there an additional value that can't be easily quantified? I think that and other issues need to be explored.
There used to be a blog about that kind of stuff called Animalblawg, but they are no more :-(.