But why, no really, I get that we're technically at fault, but the world changes, there are billions (about 5 billion to be exact) of extinct species, which ones do we pick to un-extinct? Do we have to prove that we or one of our ancestors was a direct cause for the extinction? And when we do un-extinct a species, what does that achieve, other than entertainment for some few people and maybe the feeling of having achieved something "good"? Surely the money spent researching this could be better spent making the world as it is a better place and improving ways in which humans interact with the world to reduce extinction rates and general harm to the environment.