Strange, I don't think anyone has mentioned rights in this thread so I'm not sure why you raised that issue but seeing as you have, let's explore it. People with learning difficulties, terminally ill people or even new born babies are to varying degrees incapable of fulfilling reciprocal resonsibilities to society so I think you can't argue for experimenting on animals alone on those grounds. I would in fact disagree with this utilitarian attitude to 'rights' in any case but I don't want to get dragged down a side alley as I'm not sure it's a useful concept in this area.

The question of whether society places a higher value on one set of beings than another cannot be an argument for inflicting suffering. In Nazi Germany, Jews, homosexuals, gypsies, Poles, and many other groups were considered of lesser value by that society - and were subjected to appalling experiments. In my own society upper and middle classes have a higher value placed on them than working class people. At various times it has been considered entirely acceptable to cause suffering to other races, religions, tribes etc by most societies so I think you are going to have to make a better case for what makes animals so different that you can cause suffering to them for other beings.