Good idea to devote a separate thread to this interesting topic!
Here's my reply to this video on the other thread:
inkling, Thanks for posting this impressive video on bonobos. Very interesting the researcher says that cultural exposure plays a more important role than biology (by the way, this makes us rethink the fancied importance of speciation). In the 16th century native Tasmanians were reported to lack any stone tools, fire and even music. Should they receive human rights? Of course, what makes us human is to a large extent culturally determined. So, when our closest relatives in the animal world are treated respectfully and given rights they start to behave human-like including (written) language, music and toolmaking. I believe this is the most civilized decision to take.
http://www.jehovahs-witness.com/6/161193/3.ashx