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First-time expectant orangutan, Batu, on 24-hour birth watch as she nears end of pregnancy

Posted by Gigi Allianic, Communications

An orangutan at Woodland Park Zoo, 14-year-old Batu, is expected to give birth soon and is nearing the end of her pregnancy, which for orangutans is nearly nine months. The birth will mark the first orangutan born at the zoo in 35 years.

Birth window calculations are based on estrus cycle, physical changes including weight gain, timing of mating and positive pregnancy test results. As a result, it is not possible to accurately predict a specific birth date, but recent changes indicate it is approaching.

A pregnant Batu, photo by Laura McComesky/Woodland Park Zoo

The birth management plan tailored for orangutans at the zoo includes 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. 

Just as for human women, ultrasound imaging is non-invasive, painless and safe. 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 due any day now! Photo by Laura McComesky/Woodland Park Zoo

“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 Dr. Tim Storms, Director of Animal Health at Woodland Park Zoo. “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.”

Batu, which means “rock” in Malay, arrived in 2021 from Philadelphia Zoo. The first-time father-to-be, Godek, whose name means “sideburns” in Indonesian, arrived in 2017 from Cheyenne Mountain Zoo (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. Species Survival Plans are cooperative breeding programs across accredited zoos to help ensure healthy, self-sustaining populations of threatened and endangered species.

Throughout Batu’s pregnancy, the orangutan care team has been providing maternal skills training to help equip her with as many skills possible to instill confidence and help her be a successful mother.

Female orangutans give birth every seven to nine years only, which is an exceptionally long birth interval for a mammal. Among the great apes (orangutans, gorillas, chimpanzees, bonobos and humans), infant orangutans have the longest infant development period. They are completely dependent on their mom for the first three to four years while nursing and are carried by their moms. Mother orangutans become empty nesters when their babies reach about 7 to 8 years old. 

Godek and Batu, photo by Jeremy Dwyer-Lindgren/Woodland Park Zoo

The zoo currently 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 passed away.

There are three species of orangutans that are found only in Southeast Asia: the Bornean orangutan native to the island of Borneo, and Sumatran and Tapanuli orangutans native to the island of Sumatra. A critically endangered species, orangutans belong to the family Hominidae, which includes all five great apes: gorillas, chimpanzees, bonobos, orangutans and humans.

Orangutans face threats including habitat loss and fragmentation due to forest fires, logging, and conversion to unsustainable monocultures, such as palm oil plantations. Habitat loss is also projected to be exacerbated with climate change. Additionally, these animals are illegally hunted for meat and in response to human-wildlife conflict. 

Batu and Godek on Trail of Vines. Photo by Jeremy Dwyer-Lindgren/Woodland Park Zoo

Take action for endangered species this Halloween season, and any time you crave something sweet, with our wildlife-friendly candy guide: zoo.org/palmoil 

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