While moving furniture about in the bedroom, we put a night stand across the bathroom doorway from a moderately high wooden bookshelf. Whitey hopped up on the empty nightstand, looked at the top of the bookshelf ... and Clark Kitty transformed into the one true Spider-Cat.
Katherine and I watched, amazed, as Whitey's focus narrowed to the top of the shelf. He measured, coiled, relaxed, measured again, coiled ... and launched himself across the doorway to the shelf. He only made it by his front claws, but that's not issue for the Spider-Cat -- dangling from the side of the shelf, he pulled himself up to the top of his new conquest.
That was four feet horizontal, four feet vertical, or 68 inches straight line (5 feet 8 inches at a 45 degree angle) that he jumped. We measured.
We moved a cat tower next to the bookshelf to ease his descent, and moved the nightstand out of the room before Spider-Cat could stage an encore at 3 AM.
I wonder what the claw marks in the top of the shelf look like.