They're often out prowling and hunting and climbing, and seldom come when you call.
But sometimes they right in front of your eyes and you have no idea, as one woman, who called herself Ms. Wallace on online noticeboard Reddit, hasdiscovered.
She said she spent 10 minutes searching her house for her cat, whose name is Clancy.
She went outside, did a sweep of the living room and bedrooms, but nothing.
