The Zoo houses two white-cheeked gibbons and two siamangs at Gibbon Ridge.
Male white-cheeked gibbons have black hair and skin with white hair on their cheeks and a pronounced crest of hair on the crown of their head. Females are a more golden blonde with a black face and dark hair capped, instead of crested, on the top of her head.
Male and female siamangs are black. They are the largest of the gibbon family and are the best at walking on two legs.
White-cheeked gibbons at Gibbon Ridge:
Muneca – female
Muneca is the oldest resident of Gibbon Ridge, born in about 1967. She is a white-colored adult female with a black cap. Often, her hair turns a gold color in the summer. She is skinny and has a slightly curvy spine. She has poor eyesight—visitors may see her looking at her food and enrichment items up close.
She initiates vocalizations among all the gibbons. She seeks attention from keepers by presenting her back to get groomed. She enjoys swinging on the vines outside.
Sydney – male
Sydney is a young adult male with the typical all black body and white cheeks. He was born at the Zoo in 1999 to Ralph and Siam. As with all white-cheeked gibbon babies, when Sydney was born he had blonde hair. Males' hair turns black around the age of three.
He is very active, swinging on ropes and vines indoors and outdoors. The National Zoo is working with the White-Cheeked Gibbon SSP to find Sydney a female to pair him with.
Siamangs at Gibbon Ridge:
Bradley – male
Bradley, born in 1996, is the more active of the two siamangs. He often solicits play with Ronnie. Every morning they have a play session, pushing and slapping each other around, vocalizing, and swinging on ropes. When Bradley gets excited, he likes to jump up and down and make a short boom vocalization.
He can be identified from the rear by a tuft of hair that sticks out like a tail. He is smaller and more slender than Ronnie.
Ronnie – female
Ronnie, born in 1988, is larger than Bradley and has a white mark on the bridge of her nose. She has dry skin on her belly, nose, and knees. She often looks grumpy because her brow covers the tops of her eyes.
Ronnie is slower moving, but if she wants something she’ll let her keepers know by making a soft squeaking noise.
Each group of gibbons is fed once a day. Keepers place each animal's diet throughout the indoor enclosures to encourage movement and choice. The Zoo's nutrition staff prepare the diets with a mixture of greens, vegetables, fruits, and biscuits high in nutritional value. Diets can include kale, cabbage, romaine lettuce, dandelion greens, collard greens, green beans, carrots, sweet potatoes, banana, apple, papaya, melon. Amounts of food depend on the ages of each animal and the ages of each group.
Throughout the day, the gibbons can receive a certain number of calories beyond their daily diet. This is given in different forms of enrichment: forage, puzzle feeders, in and on various objects to challenge them. Each animal also receives one cooked egg per week.
Each animal has a regular physical, including a dental checkup. Fecal samples are checked twice a year to make sure that animals don't have any parasites. Animal keepers observe the gibbons' behavior daily. The apes are weighed once a month.
With their long arms and legs, gibbons are adapted to swinging and moving fast high in the tree canopy. The Zoo's tall indoor and outdoor gibbon enclosures are fitted with platforms, ropes, and swings to allow the apes to navigate their habitat. They will travel in arm over arm motion called brachiation. When walking on the ground, they will place their arms above their head for balance, and walk on their two legs.
The indoor enclosures are located beneath visitors who are standing on the viewing deck of Gibbon Ridge. The Zoo's gibbons can often be heard in the early morning calling back and forth to each other. Except for winter, the gibbons usually have access to the indoors and outdoors 24 hours a day.