`CATS & DOGS' OPENS NO. 1 AT $21.7M.(ARTS & ENTERTA)

Byline: DAVID GERMAIN Associated Press

LOS ANGELES -- The fur flew at movie theaters over the weekend.

``Cats & Dogs,'' a family film about household pets feuding over world domination, debuted as the No. 1 movie with a weekend gross of $21.7 million, according to studio estimates Sunday.

The movie was a whisker ahead of the horror spoof sequel ``Scary Movie 2,'' which took in $21 million.

Both movies opened on the Fourth of July, with ``Cats & Dogs'' racking up $35.7 million in its first five days and ``Scary Movie 2'' grossing $34.5 million.

``A.I. Artificial Intelligence,'' last weekend's No. 1 film, slipped to third place with …