The Cincinnati Zoo and The Gorilla Foundation both say they're not allowed to comment on Monday's mediation. However, the zoo says it intends to file a response to the foundation's position on Thursday.
A federal judge ordered the sides to mediation in a dispute over the future of a gorilla named "Ndume."
The 37-year-old silverback was loaned to the California-based foundation in 1991 as a companion for the famous gorilla "Koko."
The zoo says the foundation is in breach of contract for not returning Ndume following Koko's death in June of last year. The foundation says Ndume isn't fit for a public zoo environment and worries the transfer could lead to his premature death.
Zoo officials say Ndume needs to be in an environment with other gorillas because of the social nature of primates. He is currently the only gorilla living at The Gorilla Foundation.
The foundation says it wants to bring other gorillas to live with Ndume but efforts to do so are hampered by the Association of Zoos and Aquariums, which controls such moves and is siding with the Cincinnati Zoo.