I have had 2 splits so far. The most obvious thing I noticed is a stretching of the foot. 1st it happened on the glass, got to see everything. 2nd it stretched it's foot out onto 2 different rocks and just pulled itself apart. I have heard it starts at the mouth, in my case I could not see the mouth. If you want pictures I could show you. At night couldn't say if they "sleep" or not, mine deflate quite a bit at lights out. I think it is from lack of light and for protection from preditors maybe. : )