Why do people continue to commit acts of animal cruelty?

Why is it that just about everywhere you look, someone is commiting an act of animal cruelty? Is it inherent; an evolution of the hunter instinct of our ancestors? Because it seems as though that from childhood, we are taught subliminally to mistreat animals: to eat their flesh, to wear their pelts, to take them from their natural environments and use them as slaves, or merely another entartainment medium (such as a circus, a zoo). Why do we do it people, and what will it take to end the suffering?