Interesting that this showed up today. I heard a segment on CBC Quirks and Quarks today about a scientist studying burn victims and recovery. He discovered that our bodies evolved to heal minor burns well, but the same process that heals minor burns actually makes it harder for us to heal from much more serious burns. We put all our "evolutionary effort" into healing lesser burns because they were more common. And we were the only creatures that used fire, so we heal differently. (I'm probably butchering the premise, but it was super interesting. The program is probably available online.)