No, he is using this cave twice in a row.
Since I placed this one (it floats at the surface) he ignores the two other caves at the ground. Astonishingly he changes its colour to beige when he is sitting in the cave. If he leaves it (e.g. for food) the “normal” darker colours come back.
The cave is made of “plastic” and it normally contains chocolate. The size is nearly the same as a film canister, but I was’nt able to get such a film canister here, so I looked out for an alternative.