Technically, Nicole is larger than a teacup Chihuahua, so I guess it makes sense

Like an unfeeling automaton, Paris Hilton has traded in her teacup Chihuahua, Tinkerbell, for a smaller one named Bambi. A "pal" says, "[Paris] only likes them when they're very small, and Tinkerbell got too big."

Which is ironic, because as soon as Nicole Richie got very small, Paris dumped her.