Who is Crookshanks, sworn enemy of the one named Scabbers?

Crookshanks, the ginger cat attacking Scabbers with murderous intent, is a much more established character in the book. While we see the furry predator occasionally leaping at Peter Pettigrew in his animal form, Crookshanks appears much more in the Prisoner of Azkaban book and on.

This cat captured so much attention that several fan theories sprung up about its origins. The most interesting one is probably a theory about Crookshanks being Lily Potter’s cat, whom she instructed to guard Harry after his death.

When did Hermione purchase Crookshanks?

Right after Harry escapes Dursley’s home and the weird bus picks him up, it drops him off at the Leaky Cauldron. The movie never specifies how long Harry is there, but it is weeks in the book. Ron, Hermione, and Harry get together there eventually and go to look for familiars together.

Ron is there fresh from a family vacation in Egypt. The entire Weasley family took a group photo there, along with Scabbers, which ended up in the newspaper. This photo is seen in the movie, and it is how Sirius Black learns of Scabbers aka Peter Pettigrew being alive and after Harry.

When they get together at the Leaky Cauldron, Ron complains that his rat is unwell, so they all go to the vet. Hermione is there with some extra cash, 10 galleons, and she did plan on purchasing a familiar. But she was initially thinking about an owl.

An excerpt from the book

They made their way back up the crowded street to the Magical Menagerie. As they reached it, Hermione came out, but she wasn’t carrying an owl. Her arms were clamped tightly around the enormous ginger cat.

“You bought that monster?” said Ron, his mouth hanging open.

“He’s gorgeous, isn’t he?” said Hermione, glowing.

That was a matter of opinion, thought Harry. The cat’s ginger fur was thick and fluffy, but it was definitely a bit bowlegged, and its face looked grumpy and oddly squashed, as though it had run headlong into a brick wall. Now that Scabbers was out of sight, however, the cat was purring contentedly in Hermione’s arms.

-Taken from the book Harry Potter and the Prisoner of Azkaban

The animosity between Crookshanks and Scabbers is instant, and the cat indeed chases him as it feels something is wrong with the rat. We later learn that Crookshanks did warn Sirius Black, in his dog form, about Scabbers.

Did Crookshanks belong to the Potters?

The ginger cat did help in exposing a dangerous enemy of Harry’s, which is the main argument for this theory. Crookshanks is a half-Kneazle. In the Wizarding World, this species has an innate ability to sense untrustworthy individuals.

Her eyes are a bright yellow and she has ginger fur, almost like a lion. Crookshanks is a magical pet, and she was in the Magical Menagerie for a long time before Hermione purchased her. The saleswoman does not specify for how long though.

Lily Potter’s letter mentions a cat

In the last book, Harry Potter and the Deathly Hallows, Harry discovers a two-part letter from his mother to Sirius Black, in his house. The letter mentions a cat, although it does not mention color or a name.

The assumption of this theory is that, when Voldemort killed James and Lilly, the cat ran away and eventually ended up in the Menagerie. Crookshanks liked Harry and tried to help Sirius Black enter Hogwarts so they could get to Peter Pettigrew.

J. K. Rowling occasionally answers a fan theory and confirms when someone is on to something. But our beloved author did not address the question of the origins of Crookshanks. However, she also changes Harry Potter canon occasionally, so there might be a bigger part to play for this ginger feline friend.