A dog bit off the finger of a 24-year-old Boulder man yesterday afternoon as the man tried to break up a fight between two dogs by sticking his hand in the middle of the scuffle.

"The victim is still in shock," said Lisa Pedersen, chief executive officer of the Boulder Valley Humane Society.

Pedersen didn't know if the victim's finger — which was bitten just below the nail — was saved.

The incident happened shortly after 4:30 in a north Boulder neighborhood, Pedersen said.

A border collie, owned by the victim, and his sister's pit-bull mix got into a fight, and it wasn't clear which dog bit the man. The family was introducing the two dogs to each other at the time of the altercation.

The pit-bull mix required veterinary care for its injuries.

"We've seen severe bites before," Pedersen said, "but I don't recall a time when a body part was bitten off."

Both dogs were placed in quarantine last night, which is routine procedure after a person is bitten. The dogs will be isolated for 10 days to see if they show signs of rabies.

The best option to break up a dog fight is to throw water on the animals, Pedersen said. If that doesn't work, using a barrier — such as a broom — between the dogs is the next best choice.

"Never stick a body part between two dogs that are fighting," she said.