A Stamford woman is listed in critical condition after sustaining severe injuries to her face and body at the hands of a pet chimpanzee Monday.

Charla Nash, 55, was mauled by a 200-pound chimpanzee named Travis outside the home where the chimp lived with its owner and Nash?s friend, Sandra Herold. Police later shot and killed the animal.

Investigators say Travis might have turned violent because he did not recognized Nash, who has shorter hair than his owner, or because the chimp had Lyme disease. Antoher possible explanation, police say, is that Travis drank tea laced with Xanax that came from a third party.

"Early on, it does not appear that this was prescribed to the chimpanzee,? says Capt. Richard Conklin, of the Stamford Police Department.

Herold owned Travis for all 14 years of his life, and it was legal for her to keep an exotic animal.

However, a spokesman for the Bronx Zoo says chimpanzees are wild animals that do not co-exist well with humans.

Stamfordwoman injured in chimp attack