Is a cat's day shorter than a human day?

This question stumped Google.
The answer to this question is a day is a day no matter what species you are.
The answer to the question, is a cat's daily cycle shorter than a human daily cycle? is.
Cats are mainly diurnal meaning they're awake during the day. Cats can sleep and wake frequently throughout a 24 hour period, they don't call it a cat nap for nothing.
So, no, a cat's daily cycle is not shorter than a humans.

Professor Threepwood's answer:
When I was going out to the shop for some refreshments I locked a cat in the coal cellar.
I awoke that evening in the park and some scally had pissed in my trousers!
When I got back home I let the cat out. I bet that was a long day for him!
It wasn't even my cat!