It has taken one of mine 4.5 years to work out the house has an upstairs. She used to sit at the bottom of the stairs looking upwards sometimes with a curious look on her face, but she lacked the brains to work out how to climb the stairs. She'd watch the other cat stroll past her and just seem bewildered.
Anyway - suddenly she's mastered the skill and it's like she has a whole new playground. She is one happy cat.
Are there stupider cats out there?