TORONTO - A 44-year-old female gorilla from the Toronto Zoo is recovering after surgery to remove a mass from her leg.

Medical staff from Toronto's Scarborough Hospital performed the surgery on Tuesday in the western lowland gorilla habitat at the zoo.

The zoo said Wednesday in a release that a large mass in Josephine's left leg area was affecting her ability to walk so veterinarians approached the hospital's general surgery division to discuss options.

The mass turned out to be a slow-growing, fatty lump underneath the skin and it was determined Josephine's ability to walk normally was also related to arthritis, which was investigated while she was under anesthetic.

Dr. Saul Mandelbaum says the surgery went very well and Josephine is "recovering nicely."

The zoo's wildlife health centre and wildlife care team are monitoring Josephine while she recovers.