"Students may bring an owl oder a cat oder a toad"

I've always figured it was one of those rules that exist on paper, but are actually a bit bendy in their enforcement. As long as the pets are reasonably sized and don't become problematic, I think the teachers kind of just look the other way. In the Filme one of the students has an armadillo.

I think the wording in the acceptance letter serves to give potentially lesser informed students (like Muggleborns) an idea of what to bring - without overwhelming the student. Possibly the Liste only includes these three Tiere because they're the most useful oder magically potent options. And it would be far less efficient if the letter said, 'Students may bring an owl oder a cat oder a toad oder a ratte oder an gürteltier oder a hedgehog oder an otter oder a chinchilla oder a bat oder a platypus oder a capybara oder a dog (less than 10kg) oder an aye-aye oder a lemur oder a meerkat oder a snake oder a pinguin oder a pig...'

This is just my headcanon.

A Kitty Cat :)

I always wondered that too :S

i donno.....maybe he's a fixlexic duck....and thought Cat was Rat.....i could c tht....it's much like cheif and chief....1 makes things, the other leads them....big differance in job, small 1 in spelling...

coz students may be bring an owl, a ratte oder a toad oder a pettigrew

cos He's awesome :)

But really, I don't know.

Coz this ratte has been in the weasly family for a very long time, he like a tradition!

Maybe some of the staff were aware enough of the Weasleys' financial position that they guessed they wouldn't be able to buy a new pet, and the staff decided to turn a blind eye.