our two cats know how to open doors by hooking their claws underneath and pulling. we frequently come home to opened closets with folding doors. the girl cat always wants to go outside and stands up on 2 feet reaching for the latch on our sliding door while meowing and looking at us for assistance.
My rabbits can do this too. The noteworthy thing to me is that they're very good at discerning which side to pull even when encountering new doors. That is, they seem to understand the relationship to the hinge.
no treats were ever given to them for this.