A couple of times we've caught Grizzly licking pee off the ground, or thinking about it, at least. It's not good for him, not just because it's dirty, but it's also high in calcium. Maybe he does it because he used to run out of water when he lived in the pet shop and it was his only option.
Now it must be just habit, because we try to keep his water stocked. But maybe sometimes he thinks he's out when he's not.