Philadelphia Zoo Announces Birth of Sumatran Orangutan

Philadelphia Zoo is proud to announce the birth of a critically endangered Sumatran orangutan, the first birth of this species at the Zoo in 15 years, and a significant birth to the population of these animals.

Born to the Zoo’s 31-year-old female Tua and 28-year-old male, Sugi, on June 26, the infant continues to look strong, and Tua continues to be an excellent mother, nursing and holding the baby at all times. The sex of the infant has not been determined and a name has not been chosen. Mom and baby are currently setting their own schedule for when they will be visible to guests. They have access to their indoor habitat where visitors may get a glimpse of them but also have access to their bedroom space to spend time alone. The Zoo is planning to have their big public debut sometime in mid-August and invites everyone to join. More details on the celebration to come soon. The baby’s birth is a part of the Association of Zoos and Aquariums (AZA) Species Survival Plan (SSP) breeding program to ensure the survival of Sumatran orangutans and maintain a genetically diverse population. Sumatran orangutans are listed as critically endangered by the International Union for the Conservation of Nature (IUCN) with a population of 14,000 left on the island of Sumatra. Primary threats include deforestation and population fragmentation.

“It is a joy to be able to share this wonderful news with the greater Philadelphia region and the world,” says Vice President of Animal Well-Being and Conservation Rachel Metz. “This critically endangered species is rapidly losing habitat largely due to deforestation as a result of an increased demand for logging, palm oil, and other natural resources located in their habitats. Working with the Association of Zoos and Aquariums to maintain a genetically healthy population in human care is vital to the survival of this species.”

“Our entire Zoo Community and those that work closest with our orangutans are thrilled to watch Tua become a mother again and watch this baby grow,” says the Andrew J. Baker Curator of Primates and Small Mammals Michael Stern. “It is an honor to care for and work with these animals, and we all feel the magnitude this birth has in the protection of this species.”

“This successful outcome is a testament to the animal care, nutrition and veterinary teams that have worked with Tua to greatly improve her health over the last eight years,” says Director of Animal Health Dr. Donna Ialeggio. “Finding practical strategies to both maintain a healthy weight and treat her chronic Orangutan Respiratory Disease Syndrome with twice daily nebulization therapies are a testament to the ingenuity and dedication of our staff.”

In 2009, Tua successfully gave birth to and raised one female offspring, Batu. Batu stayed with Tua and Sugi at the Zoo through 2021. When the time was right and she and her family showed the behavioral signs it was time for Batu to leave her family, the SSP paired her with a male at Woodland Park Zoo in

Seattle, Washington, where she is now expecting her first baby this September. In 1928, Philadelphia Zoo was the first to successfully breed orangutans. Since then, the Zoo has had 19 more successful births.

Orangutan babies are born after an 8-month gestation and are totally dependent on their mothers. The baby is able to cling to its mother’s fur. Babies will nurse from their mothers for up to 6 years, but can start eating solid foods at 4 months old. Offspring will stay with their moms until they reach adolescence at 7 to 10 years old. In the wild, fathers typically don’t play a role in raising the young; in zoos, depending on personality, many orangutans do enjoy living together with their mate. After allowing time for Tua and the baby to bond, we will allow Tua, the baby and dad Sugi to be together if they choose to be. Tua and Sugi live together most of the time.

Sumatran orangutans live in primary and secondary forests of Sumatra, an island of Indonesia. They are the only members of the great ape family to spend most of their time off the ground. Their legs are short, but they have long, muscular arms to help them climb high in the trees. They primarily eat fruits, but also eat leaves, inner bark and various types of non-leafy vegetation. Orangutans are the most solitary of the great apes, but they exhibit a wide range of sociality across their range and may be extremely social when they do associate with other orangutans.