I have a couple black widows living in my basement. They each chose to live in a small crevice in a concrete wall. I can go watch them, but if my shadow acciden

I have a couple black widows living in my basement. They each chose to live in a small crevice in a concrete wall. I can go watch them, but if my shadow accidentally falls on them, they hide as fast as they can. Some people thinks it’s crazy that I don’t kill them, but they certainly aren’t trying to hurt me, so I don’t see why I would.