Zoo New England, which operates the Franklin Park Zoo, said the 36-year-old gorilla, Gigi, was put under anesthesia and submitted to the tests after suffering digestive problems and failing to respond to treatment as well as veterinarians had expected, WCVB-TV, Boston, reported Thursday.

"We did not find anything abnormal. While the colonoscopy looked normal, we did take several biopsies. We expect to have the test results back within one to two weeks," said Dr. Hayley Weston Murphy, Director of Veterinary Services for Zoo New England.

Gigi, who has been with the zoo since 1980, has mothered two male gorillas -- Quito in 1981 and Kubandu in 1982.