Scientists say dolphins should be treated as 'non-human persons'
timesonline.co.uk
timesonline.co.uk
I don't even disagree with them. It's just that whether something should be treated as a "non-human person" is a matter of values, and I don't think the common set of values around personhood has anything to do with intelligence. If you want it to, you need to change that first.
I do disagree with them though. I don't think there is such a thing as a "non-human person" let alone applying it to the animal kingdom.
Edit: PETA must love it though