One of the mornings, when Mera was very tired, and went to bed after breakfast.

I noticed that he and Hat never sleeps in the house at the same time. If Hat stays in after breakfast, Mera won't appear. If Hat leaves after breakfast, then it is quite likely that Mera would trot by at 9am. I am sure the roster is decided by Mera. If it rains, then Mera can come in anytime and hide under the bed, even though Hat is already in the house.

Even Spencer gets exasperated with the tomcats sometimes.