my rb cat, Cookie, when we brought her home, she was 10 weeks old, and we had a 6ft condo for Muffin...well she went right over to it, and just scampered up that thing like it was only 10" ! and--lol-- she would just jump straight down! a small kitten jumping down 6ft! scared me, I don't know how she didn't hurt herself!(but she must have pulled some stitches or something because as she got older, she had the wobbly flabby tummy , everytime she would run it would jiggle back and forth!