The zoo determined on Monday morning that a natural birth was not possible due to the abnormal breech position of the full-term calf. The procedure to manually remove the calf lasted five hours and required more than 30 Animal Care and Animal Health staff members. Hasina awoke from the anesthesia, but died Monday night, zoo officials reported. "This was a time-sensitive procedure and it was all hands on deck," said Beth Schaefer, director of animal programs. "When you have an animal of this size and weight, it takes a large team to manage all of the logistics that come with a procedure of this magnitude. We were all focused on the welfare of Hasina, who has been with us for years. Hasina has always been a favorite among staff and guests, and she will be greatly missed."