SEATTLE — Woodland Park Zoo officials said Monday they are expecting the arrival of its first orangutan baby in over three decades.
Fourteen-year-old Sumatran orangutan Batu (bah-too) is nearing the end of her pregnancy, which is nearly nine months. The birth will mark the first orangutan born at the zoo in 35 years.
According to the zoo, birth window calculations are based on estrus cycle, physical changes including weight gain, timing of mating and positive pregnancy test results. It is not possible to accurately predict a specific birth date for orangutans because of several factors, but officials said recent changes indicate it is approaching.
Zookeepers said its birth management plan is tailored for orangutans at the zoo, including a pre- and post-natal care program, which includes regular veterinary check-ups in consultation with an obstetrician gynecologist, ultrasound procedures to track fetal development, a diet created by a nutritionist, and supplemental vitamins to help Batu maintain a healthy weight for a delivery without challenges.
Similar to human women, ultrasound imaging is non-invasive, painless and safe for orangutans. The zoo said ultrasound procedures are attempted a few times weekly on Batu to monitor fetal growth and visualize fetal movements, development and cardiac function. Ultrasounds are made possible through focused training sessions by the zoo’s orangutan care team which stem from a trusting relationship between the patient and caretakers but are dependent on Batu’s cooperation.
“Batu is given the choice to voluntarily participate in the non-invasive ultrasound procedures, which involve her presenting her belly and holding still as we apply the ultrasound probe for imaging. Sometimes she’s not interested in participating, but we follow her cues,” said Tim Storms, Woodland Park Zoo director of animal health. “We also use a small doppler unit to monitor the fetal heartbeat. We’re pleased to report that recent ultrasound images indicate Batu is near-term and the fetus appears to be developing well with a normal heartbeat.”
The zoo's orangutan care team said it has been providing maternal skills training to help equip Batu with as many skills possible to instill confidence and help her be a successful mother.
According to a release, orangutans have exceptionally long intervals between birth, only having offspring once every seven to nine years. Baby orangutans are completely dependent on their mothers for the first three to four years of life. Mothers do not become empty nesters until their offspring are around seven to eight years old.
The Woodland Park Zoo has four orangutans who live in two family groups: Batu and Godek share a habitat while 35-year-old male Heran and 43-year-old female Belawan (Bela) live in the other orangutan habitat. Heran was the last orangutan born at Woodland Park Zoo in 1989. His parents have since died.
Batu, which means “rock” in Malay, arrived in 2021 from the Philadelphia Zoo. The first-time father-to-be, Godek, whose name means “sideburns” in Indonesian, arrived in 2017 from Cheyenne Mountain Zoo in Colorado Springs, Colo.
The Sumatran orangutans were paired under a breeding recommendation by the Orangutan Species Survival Plan and have been companions in the zoo’s Trail of Vines, according to a release. Species Survival Plans are cooperative breeding programs across accredited zoos to help ensure healthy, self-sustaining populations of threatened and endangered species.
