So we meet again Typical_08, I am going to go with "To protect his family." No I am not nor have I been in the military but I have many family members who have and I have discussed this very topic with a psych professor or three. A man would jump on a grenade, and not every man mind you, to protect his buddies when he has been conditioned to believe those buddies are his family and he has been removed from his family for an extended period of time. Societies entire purpose is to override the instincts we have that do not better the group and bolster the ones that do. The military does the same thing in its training to a greater degree.
I would agree. It has nothing to do with instinct. But it has more to do than just them being family. I don't know if I can accuratly explain it.
Again I am with you on this one. Snakes just don't have the parts of the brain for this kinda thing.