A lever trap doesn't differentiate - it will insta kill a hare, or one of my cats, or some of the neighbours' cats... But, yes - at some point I was half-seriously thinking about some kind of structure which is easy to enter, but not so easy to find a way out. Something which would trap animals unharmed, so that each morning I could check if there is a hare, or a cat, inside. Maybe I'll start constructing that kind of structures if the mainstream society (or the food supply chain) collapses...