The Obamas' dog, Sunny, has a disposition that fits her name, and until this week she's never chomped down on anyone.
We broke the story ... the Portuguese Water Dog bit a family friend in the face Monday during a visit to the White House. The wound required stitches and she may end up with a permanent scar.
We've been in touch with people who are frequently around the pooch, and we're told she's never bitten anyone else -- ever. To the contrary, the 4-year-old has a loving, even temperament.
One source noted the dog gets groomed every month and 4 to 5 people are handling her at the same time while she gets sculpted with scissors and hand dried. The dog has never shown any aggression during the grooming process.
The 18-year-old girl who got bit is pissed off at Sunny, we're told, but her family is not planning any legal action.
FUN FACT: In many states, there were laws that protected dog owners from lawsuits the first time a dog bit a person. The reason -- until dog owners are on notice of aggression, it's unfair to punish them. The "One Bite Rule" -- which essentially means every dog is entitled to one free bite -- has been repealed in most states.