we love animals. they have much to offer to us humans. In Buddhist cosmology, there's no argument about the benefits of the animal kingdom. The point is that animals' behavior links itself more to instinct than to self-awareness. Human beings need to develop their self-aware virtues in order to lead a happy life more than do animals.
Animals can feel debts of gratitude, people need appreciate others more than do animals need the feeling of appreciation in order to feel joy. One of the basic Buddhist debts of gratitude we need to repay, if we subscribe to this teaching, supplies us with plenty of those to whom we can busy ourselves repaying: the debt of gratitude to all living beings.