SEATTLE — Woodland Park Zoo will not be the same without the distinctive barks and hoots resonating from its pair of siamangs, an endangered primate. Yesterday, zoo animal health staff euthanized a 16-year-old female, Sai Buri (sigh-BOOR-ee), due to a massive inoperable tumor. Final determination of the tumor is pending pathology exams of the tissues.

The death of Sai Buri leaves behind the zoo’s only remaining siamang, 17-year-old Simon. The two siamangs have lived together at the zoo since Simon was transferred here and introduced to Sai Buri in 1982. After living in both the old-style Ape House and Primate House for nearly 15 years, the pair was shifted in 1995 to an open, naturalistic habitat in the Trail of Vines.

Throughout this year, the lesser ape had been treated intermittently for lethargy, poor appetite, weight loss and constipation. As a result, zoo animal health staff last month administered an extensive work-up on Sai Buri that included ultrasound and radiographs by zoo volunteer radiologist Dr. Rob Liddell with Radiology Consultants of Washington. Dr. Liddell uncovered substantial amounts of gravel and sand in her intestines.

Despite extensive efforts by zoo keepers to improve Sai Buri’s activity level, attitude and appetite, her lethargy and poor appetite during the last two days prompted zoo animal health staff to immobilize her for further examination. Upon discovering an abdominal mass, they immediately performed abdominal surgery and found the tumor involving her stomach and small and large intestines. "We could not have treated her effectively," explained zoo Senior Veterinarian Dr. Janis Joslin. "Since Sai Buri’s chances of survival were slim, we felt the most humane alternative was to euthanize her."

Sai Buri and Simon were extremely popular animals for zoo staff, visitors and neighbors by virtue of their elaborate ear-splitting duet. "Their vocalizations could be heard throughout the entire zoo and as far away as lower Queen Anne," said zoo Senior Keeper Helen Shewman. "Now that Simon’s alone, his solo calls will be nowhere near the intensity and duration as his and Sai Buri’s duet. Everyone will undoubtedly sense this void."

For this reason, the zoo will undertake a concerted search to find a new companion for Simon. "We will continue to work cooperatively with other captive siamang programs in any way we can for the benefit of this endangered species," added Shewman. Under managed programs for siamangs, Sai Buri and Simon could not breed because they shared a common grandparent and therefore, were too closely related.

Sai Buri also drew special attention because she was missing one arm. At two months old, she sustained an injury on her arm from her father during a parental squabble, and consequently, had the arm surgically amputated. As a result, Sai Buri was handraised by zoo staff, and although Children’s Hospital & Medical Center specially designed a prosthetic arm, she was able to get along fine without it. "Because she was so athletic and dexterous, in spite of only one arm, it was difficult to notice she was disabled," noted Shewman.

Siamangs are native to the island of Sumatra and the Malay Peninsula. The largest of the 11 lesser ape species, siamangs pair-bond for life and form territorial areas which they guard. Their singing communicates location between different family groups, establishes and maintains feeding boundaries, and helps maintain and further develop bonds between a mated pair.