There is a general view that to inflict cruelty on a human being is worse than inflicting it on an animal.?

But is this view truly rational or merely an evolutionary species bias survival instinct etc ie harming ones own necessarily seems more morally grievous to us. I guess it could be argued that we are higher order creatures and rational beings and so have more intrinsic worth and value hence to harm humans is worse. But arguably what makes cruelty repulsive is the fact it and degree to which it causes emotional and physical distress pain and suffering. Arguably other higher order animals can experience this as acutely as human beings so where is the justification for the above view. Is it as we are more rational and hence we do feel pain and suffering more acutely or just more complexly? Discuss.