From Nookipedia, the Animal Crossing wiki
Tanuki are a species of character in Animal Crossing. Tanuki are frequently confused with raccoons in Western culture (and referred to as raccoons in-game). All Tanukis so far have been special characters, and worked in the same place, similar to Pelican characters.
 Special Characters
Timmy and Tommy are twins, and are Tom Nook's Nephews. They only work in Nookington's on the second floor. In Animal Crossing: New Leaf they work at Nookling Junction and its upgrades, T&T Mart, Super T&T, T.I.Y., and T&T Emporium.
Tom Nook is the main Tanuki in the game, being one of the first special characters to appear. He is the one who built the players house, and expands it, as he is the one you pay mortgage to. In Animal Crossing: New Leaf he works at Nook's Homes.
 Connection with Furniture/Leaves