Why is the heart not in the middle of the body?

Question

All mammals that I can think of have a high degree of bilateral symmetry (In fact, almost every animal I can think of is like this).So why is the human heart not exactly in the middle of the body? An effect of this is that one lung is slightly smaller. Are there any evolutionary theories on why this came to be?

Answer 1

I'm not sure there is a correct answer to this question but it's a very interesting one! The main thought that came to my head was the lung idea, but is the left lung smaller to make room for the heart? We may never know.