Why sleeping through the night may not be natural. Our ancestors usually slept in two intervals each night, rather than one that most people do now. I've slept in three or four each night through most of my life, waking up to eat or read in between intervals.
For some reason a giant water bug was crawling around inside my building. I picked it up and placed it in one of our freshwater exhibits. I discovered later that its bite is one of the most painful of any living insect, so I guess I lucked out. Here's one attacking a fish.