Animal rights, if framed that way, seems a bit off. Though the more interesting question (that is directly related to all these) is at what point we should honor life of other species? So far mankind treats pretty much every other animal as if they were just there to serve us.

Is this just about respecting life? Why not all life?

What if we were to aliens as ants are to humans?

How are we different from ants, anyway?

More examples of current treatment (sentience acknowledgement and emotional attachment)

I think it's quite a mess. And we are only lucky that so far other species haven't tried to claim revenge on us for our lack of respect for them.

If only it were as easy as just not mingling with other species.

Though, for the near future, I think the definition that will apply to new entities (what Gregol was hinting at) is drawing the line at sentience when communication is possible.

If you can give an order to "something", and they can reply "why should I do as you say?", then they probably deserve "human" rights and respect.

I don't understand so well the second question as to comment on it. :B