I went to the zoo with my kids and had this conversation with my 3yr old daughter:
We look into the elephant area and she says with authority: "Elephants can't hurt me."
I don't want to scare her but I want her to be careful, so I say something like "Well you know, they are very big, and they could hurt you without meaning to, if you got too close ..."
This really upsets her, and with a tear in her voice she exclaims: "But EEE-muh, elephants can't hurt me! They don't have STINGers!"