Bless

I had a cat would use the cat flap as a knocker if we were there - it saved him having to catch the end of his tail as the flap came down behind him!
He would also use the bell on his collar as a doorbell.
I had another cat spent an hour one morning experimenting with ways of going through the flap to find a way which didn't catch the end of his tail. He even tried holding the flap up with his back foot and swishing his tail through before dropping his foot.
Dumb animals? I don't think so!