I had considered that also. For some reason, though, I tend to see reproduction as less primitive to survival than digestion. EDIT: Less primitive to surviva

I had considered that also. For some reason, though, I tend to see reproduction as less primitive to survival than digestion. EDIT: Less primitive to survival of the animal itself, not of its species. In fact I'm not 100% sure that survival of the species is critically important. It just so happens that all of the animals that are still here are the species who do have a raging desire to procreate.