“Whoop, Whoooooop, Whoop-whoop!”

There’s a new set of sounds heard throughout Point Defiance Park, coming from Point Defiance Zoo & Aquarium. It’s the sound of two young lar gibbons singing loudly in unison.

Also known as white-handed gibbons, they are an endangered primate in the gibbon family with around 15,000 currently living in the wild. They are among the most agile animals on the planet and move easily through trees in the forests of Southeast Asia by swinging hand over hand with their body suspended below.

Aries, 4, and Orion, 7, are brothers, born and raised at the Philadelphia Zoo. The brothers shared their habitat in Philadelphia with a few other gibbons and needed their own space. That’s where Point Defiance Zoo stepped in and agreed to provide a new home for them.

Aries and Orion now live together in the Zoo’s Asian Forest Sanctuary and are often heard singing or seen swinging together (lar gibbons can leap up to 26 feet between branches!). In the wild, their distinctive song, enhanced by a sound-amplifying throat sac, lasts an average of 11 minutes and can be heard over half-a-mile away.

“Aries and Orion sing 2 to 3 times a day, and at least once in the morning,” said assistant curator Steven OK. “We recently heard them sing for 30 minutes!”

Their Personalities

The brothers are still considered young for their species. Lar gibbon males mature late at 8 to 12-years-old. In fact, gibbons have one of the longest juvenile periods among nonhuman primates. Zoo visitors will notice just how much energy they have and how playful the two can be.

“Aries is very athletic, often showing off by doing back flips through the air while swinging from rope-to-rope or playing on the floor and doing somersaults,” said staff biologist Erin Carey.

Carey says Aries is brave, and tries news things more quickly than Orion, who is more cautious.

“Anything Aries picks up, he puts right in his mouth or licks it, just like a young child,” said Carey.

Orion, being the big brother he is, tries to be sneaky and take Aries’ treats. He also likes to be groomed by his younger brother (an activity called allogrooming that strengthens social bonds), but doesn’t return the favor. Fortunately, keepers say Aries is patient and good at sharing.

Brotherly play aside, the two often huddle with their backs to each other at night when they sleep.

If visitors look closely, they will notice a few subtle differences between the brothers. Aries has slightly darker and longer/fluffier fur around his head. Orion has bigger canines.

Introducing Species

Over the next year, keepers plan to introduce the gibbons to some of the other species (like the anoa, tapirs or porcupine!). The Zoo’s Asian Forest Sanctuary opened in 2004 and includes a complex system of behind-the-scenes “chutes” to allow animals to move securely from their sleeping and exercise yards into any of the five habitats.

“This design helps stimulate the animals, allowing them to smell other animal scents and explore new areas,” said curator Telena Welsh. “The rotational habitats are designed to provide the animals with as natural of a forest experience as possible, meaning some animals are even grouped together, just as they could be in the wild.”

Point Defiance Zoo’s Asian Forest Sanctuary was considered cutting edge at the time it opened, with one of the first rotational habitats in the country.

Fast Facts

Diet

Aries and Orion eat a sizable fresh salad twice a day and primate chow at night, and are being introduced to new foods like cooked chicken, hard boiled eggs and peanut butter. Some of their favorite foods include red pepper, spinach, grapes and bananas. In the wild, lar gibbons mainly eat fruits, especially figs which can make up half their diet, leaves, buds, flowers and insects.

Habitat and Range

Their range is in Southeast Asia including Indonesia, Lao People’s Democratic Republic, Malaysia, Myanmar and Thailand. Of all the gibbon species, lar gibbons inhabit the greatest north-south range. They live in the high canopy of tropical forests and are rarely found in the understory.

Median Life Expectancy

Lar gibbons have a median life expectancy of about 16 years in human care.

Help Gibbons in the Wild

Lar gibbons are endangered, with current populations in the wild declining. The major threat to them is hunting. They are hunted for both food and for the illegal pet trade. Another threat they face is deforestation. Much of Southeast Asia’s rainforest is being destroyed to make room for palm oil plantations, making it difficult for gibbons in the wild to survive. You can help save the species by checking the products you use for sustainable palm oil and encouraging companies to make the switch.