Re: Chimpanzee or bonobo

It's often said that the chimpanzee is our closest living relative.  As 
you astutely noted, however, the bonobo shares some traits with humans 
that chimps do not.  The genetic studies I've seen indicate, though, that 
chimps and bonobos are both descended from a common ancestor that split 
from the human ancestral line about five million years ago.  So both are 
equally closely related to humans, genetically, and the relative closeness 
of one or the other that we might perceive are due to the chances and 
pressures of evolution.

One trait of the bonobo that you didn't mention is their communication 
ability.  At least one bonobo, named Kanzi, has shown a remarkable ability 
to communicate with human language.  His mentor is Dr. Sue Savage-
Rumbaugh, and you can find mention of him in this 
discussion of communication, and a longer mention in this review of 
her book.  For a more thorough discussion, of course, you should pick 
up her book, titled "Kanzi: The Ape at the Brink of the Human Mind."