sentences:  Zoo director Bill Foster argued that the stress caused by travel and resettlement would not be healthy for Mona, and that she should not, at her age, have been subjected to the behavior and pecking order of an unfamiliar herd.He indicated that the zoo planned to improve her habitat and was considering adding a companion to her exhibit.On June 18, 2007 zoo staff found Mona unable to stand on her own and assisted her with slings.