“Man is said to be the image of God by reason of his intellectual nature…”*
And, “…no real thing lacks a proper operation.”**
Animals and man have a different nature and fulfill their nature in a different way. We are called to something more than the life of an animal. Life for man is not survival, life is virtue…happiness. Life for man is not eating and drinking, life is thought.
Virtue is not simply “I’m not a bad person,” virtue is excellence…it is doing the right thing because you know it’s the right thing…it is being above and beyond. Happiness is a kind of activity…
The activity that is perfectly suited for what man is…is thinking. This is the highest happiness because it is the highest activity of the highest part of the soul. And the highest thing the intellect can do is thinking about the highest object of thought, which is God.
Our lives are not to be the same as the lives of animals. But, our interaction with animals is meant to lead us to greatness and the fullness of life. Happiness is waiting…
* ST I, Q 93
**On Being and Essence