ethical extension

researchers argue that dolphins should have more rights due to thier highly developed brain, complex societies and ability to participate in meme like behavior:

http://www.timesonline.co.uk/tol/news/science/article6973994.ece

this is pretty cool.

my question: then when do rights get extended to other species? only it they pass a human designed IQ test showing their mental prowess in relation to our own way of thinking….