When I was at school my English teacher insisted that all animals were “it”. She was shouted down by the entire class. But I’ve never heard of dogs being exclusively male and cats female, in the UK or anywhere else.
I do that sometimes, I think. I do go to the the other extreme as well, and will accuse a student orchestra of ‘playing like a bunch of girls’ when they’re 95% female (sometimes you just need to provoke them a bit!)
I’ve read several early-20th-century books by various English authors in which gender-unknown or gender-unspecified cats were referred to as “she” in contexts that suggest this was a convention of the era; of course, I can’t think of a single example at the moment… although I suspect PG Wodehouse and Dorothy Sayers are two of the culprits.
But I haven’t even heard of calling all dogs “he”.
In America, this usage sometimes persists into normal adult discourse; a current cat food commercial urges us to surprise her with the delicious product being proffered.
It rubs me the wrong way…we have four cats, all neutered males, that we collectively call “the boys”.
This is true of my grandparents’ generation. It doesn’t seem so common anymore, but I’ve heard a lot of older people refer to dogs as he and cats as she.