This is just me making up for fueling the thread hijack with the kangaroo mutilation thing
The questions stand thus:
Are animals capable of cruelty, or is the pain they cause to others driven by instinct?
What about humans gives them this quality that they use so liberally?
I currently believe that animals are incapable of the cruelty we humans may act with. Cruelty requires certain mental functions that I do not believe animals posess. Any act which may look cruel to us may be just an instinctual drive, forcing the animal to act this way, or a learned behavior to help it accomplish a certain task easier.
I also believe that humans are capable of cruelty because they can put themselves into the shoes of their "victim" and consider what they are experiencing (not just considering a reaction to their actions, like an animal might), and respond with apathy. ie: "Why don't I just pull the legs off this cricket, and watch it thrash about helplessly? It can't do anything to me!" or "Why don't I just tie this kangaroo to my SUV and lynch it across the countryside? Its pain is so hilarious, and I'm so macho for pulling this off!"
Convince me otherwise.