Let my cats out into the backyard at night . They come in and out several times overnight . A couple of nights back it was rainy . My female didn't come in the final time in the early hours . Nor did she come in for breakfast . In fact she was gone for 48 hours . Not like her . And she is not interested in being around other people . I figured because of a final downpour , that the normal scents had been washed away , and she was either lost or dead . I had read somewhere that if you set their used litter box outside , they can smell it up to a mile away . I needed the litter box indoors , for her brother , so scooped the clumps into a small plastic trash can and set it on the side porch . It took a long time for the scent to waft far enough away for her to sniff it , but she did eventually find her way home . One very bedraggled kitten , but home at last .