"It was either a very big cat or quite a small tiger."
-- Harry's description of Crookshanks shortly after their first meeting (PA4)
A cat, or feline, is a small domesticated animal that is related to lions and tigers and that is kept by Muggles and Wizards, but especially by Squibs. Cats are one of the types of pets which Hogwarts students are allowed to bring with them when the start school (PS5).
- McGonagall's Animagus form is a tabby cat with spectacle eye markings (PS1)
- McGonagall and Umbridge both have cat patronuses (DH30, DH13), and Kingsley Shacklebolt has a wild lynx (DH8).
- Mrs. Figg's cat/kneazle crossbreeds: Mr. Tibbles, Snowy, Mr. Paws, Tufty (PS2, OP2)
- A lot of cats wander around Platform 9 3/4 when the Hogwarts Express is scheduled to leave (PS6)
- Millicent Bulstrode seems to have a black one (CS12)
- Mrs. Norris, Filch's cat, is particularly disliked by the students at Hogwarts (PS8 etc.)
- Cats of every color for sale at Magical Menagerie, including Crookshanks (PA4)
- Kneazle (FB, OP1, OP2) A kneazle is a cat-like creature with special abilities in the wizarding world.
- Umbridge collects plates with pictures of kittens on them (Pm).
- Ginny Weasley loves cats (CS9)
Cats are common in the muggle world, but even they have a legend of what could be thought of as magical ability about them. Old wives tales tell of cats having 9 lives, probably because of their uncanny ability to (almost) always land on their feet, and squirm their way out of tricky situations. Cats have also long been associated with witchcraft, and have a rich mythological history.
J.K.Rowling's comments about cats in an interview:
Q: Hagrid mentioned he's allergic to cats in PS why has he never sneezed when Crookshanks was around?
A: He's never around Crookshanks very much. I'm allergic to cats and I can be in a room with one briefly. But of course, Crookshanks isn't all cat. Read 'Fantastic Beasts...'! (WBD)