The Kat Family is actually two premade families that can be found in The Sims: Unleashed and in the occupied Lots and Houses Bin that came with the Pets expansion pack of The Sims 2.
Ginia Kat is an elder who lives alone in the original Sims game. She is kept company by her cats Waggles, Boots, Scout, and Maggie.
Her daughter, Tara Kat, who is not featured in the first game is found in the second game, also lives alone and is kept company by cats. Hers include the adult cats Mickey and Samantha. Once her lot is placed it starts off with her adopting a new kitten, Faline, and worrying how her other two cats will react.