Oliver has taken to Arwen, and vice versa, better than I could have imagined. It's almost as if they get along so well because they're both toddlers. Oliver runs around the house yelling "chase me, Arwen, chase me!" and Arwen joyfully wags her tail and scrambles her loveable big puppy paws across the wood floor to try gain enough traction to chase him! May not be so funny when Arwen is no longer a 25 pound puppy, but for now, they're instant best friends!