According to Nicholas Dodman, Director of the Animal Behavior Clinic, Cummings School of Veterinary Medicine, Tufts University.
Trauma, predators, and disease take their toll on itinerant pets, and outdoor cats typically live much shorter lives than indoor-only ones do. That said, absent the things that entertain cats most, indoor life risks being very dull. Several enhancements can make the move easier. Start by installing two or three scratching posts (tall enough for your cat to stretch full-length on), in easy-to-see, high-traffic areas. I would also set up various cardboard "hidey-holes," as well as a tall cat condo that will allow him to climb up high (cats prefer multilevel settings). Add to this at least two litter boxes, one for urinating and one for defecating-- yes, cats can be that fussy.
Get some rolling balls and playthings with feathers or fur to satisfy your cat's predatory instincts. Consider, too, a window bird feeder, a fish tank, or even DVDs of wheel-running rodents.
Personally, I would bring him in immediately -- go cold turkey, so to speak -- to avoid the danger of an outdoor lifestyle. But if you're not up to that, you can gradually transition your cat indoors, keeping him inside for progressively longer periods each day.
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