I gotta be honest with you, my parents live in an area that has a lot of forest preserves and there are deer, coyotes, raccoons, etc. I don't think I've ever hit one before. I'm sure it's noticeable, right? You hear a thump, your car feels like it's going over a bump...as you do 60... Never felt that. So I honestly believe I have never ran over an animal while I was driving.
Of course, I've seen tons of roadkill in my area and sometimes it's a bit hard for me to believe, but I've never seen or cleaned guts from my tires or bumper, or anywhere on my car. Maybe dead bugs. But that's it.