I think Maru's 'mood swings' all depend on a couple different things--if he was napping when I took him out, if he's hungry, if he was already stressed out from something else, and if there are a lot of new sights and smells.

His moods range from sweet and active to extremely shy. You can tell when he's been asleep, because as we pull out the tub we hear a sad little scared hiss! We startled him! He'll be shy and hiding the whole time we have him out for cleaning. Other times he's calm and alert already as we pull out the tub, and he doesn't hiss. Those days he is fine and active when we let him out.