The definition of teacup is pretty loose. Essentially, Perry says, any "exceptionally small" dog falls under that umbrella.
No specific breed is a teacup by default. That leaves unscrupulous breeders to devise new and brutal ways to shrink an already small breed like a Chihuahua or Yorkshire terrier into something new and terrible.
Aside from Paris Hilton's dubious menagerie - she says she has 35 pets - teacups are also frequently seen at shelters.
Shelters like East Valley, where Perry often sees teacup dogs brought in.
People will return them and say, "I can't do anything with them."
As though they're expecting teacups to be like, well, dogs.
Trouble is, these pint-sized pooches are not Swiss watches. They're not ingeniously designed micro-marvels. Physiologically, tiny breeds take a licking - Perry cites tiny bones that scarcely develop, precious little exercise, overworked organs - and more often than not, they don't keep on ticking.
"They have tiny little hearts," Perry says. "And tiny little lungs. They don't last as long."