Fetch is the "indoor" way I tire/exercise my guys.
My Adult Pair rarely ever need/participate, but my younger Male and Female do. I have a rather complex Living Room, couches and tables in various locations, where a throw and bounce of a (light) toy, can create a challenge for finding it.
My new Female Chi Navi fell right in like it was second nature, and given her lightness (5.5 Lb) an agility, usually gets to the Toy first. But My Junior Male Ichabod uses his additional weight (8.8 Lb) and momentum, to take it away from her, and be THE ONE who brings it back.
By comparison, Navi's build (very slender and thin skinned) would make Her appear to be fragile, but, She is NOT. She can Tug-O-War and chase Birds and Squirrels with the rest of my guys quite well. However, when going Hunting, She just tags a long. Not much interest in actually catching anything
