Sandra Herold, the owner of the 15-year-old chimp named Travis, wrestled with the animal after it inexplicably attacked her friend Monday when the visitor got out of her car in front of Herold's home.

"She retrieved a large butcher knife and stabbed her longtime pet numerous times in an effort to save her friend, who was really being brutally attacked," said Stamford police Capt. Richard Conklin.

The injured woman suffered facial injuries and blood loss. She was hospitalized late Monday in very serious condition at Stamford Hospital, police said. Her identity was not immediately released.

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AP Photo/The Stamford Advocate, Kathleen O'Rourke