After the tsunami that hit Thailand in 2004, I remember reading about elephants that pulled up the stakes they were tied to and ran into the hills well before the tsunami hit.

Your thread got me thinking about animal behavior that may be caused by natural phenomena that we don't or can't observe. In other words, animals act up before an earthquake, but what about the times they act up due to something we can't observe.

For example, let's say there's some energy release before an earthquake that animals sense but we don't. We then observe the earthquake and remember the animals having a tizzy fit beforehand and put 2 and 2 together, aha, the animals knew before we did.

But there's all sorts of animal behavior we can't explain at all. Could some of this be due to reactions to environmental triggers that we aren't aware of? The assumption (at least according to the nature programs I watched as a kid) is often that it's something internal to the animal. But what if it's entirely external?