Vacuums that include features specifically intended to make them more effective picking up fur.
Huh. I have a garden variety Hoover as well as a big male Norwegian Forest Cat who sheds like no other cat I ever saw in the summer. My vacuum cleaner handles it just fine.
The Bissell has an knobbly attachment that kind of "scrubs" the carpet to get embedded pet hair out of the fibers. It doesn't get everything, but a regular vacuum doesn't either.
A pet vacuum is a vacuum that can handle the messes created by pets, like tons of fur that is stuck in carpet.
BUT... yes, people DO vacuum their pets to groom them:
Yikes. I suppose there's no harm in it if you desensitise the pet gently... Though I'm not sure what's wrong with just usinga specialised brush. My cat absolutely loves being brushed.
Some cats really like it, some cats hide almost before you stretch your hand to a vacuum cleaner. They are all different.
I was also asking myself the same. I think it's a vacuum especially designed to handle pet hair, they do exist. But I've also seen extensions to directly vacuum pets, so maybe they do? I am really confused about people vacuuming their pets. I don't know if the vacuums to handle pet hair also come with exertions to directly vacuum the pet and if that's common.