Smithsonian National Zoological Park l Friends of the National Zoo



Common O Line Questions

Why don’t the orangutans fall off the O Line?

Orangutans are highly arboreal animals with many physical adaptations for living in trees, such as long arms, and grasping fingers and toes. Orangutans are cautious about distributing their weight, usually holding on with two or more limbs at once. Because they are arboreal, their strongest instinct is to hold on. They are also able to judge the distance to the ground.

Why don’t they escape?

They do not escape because the wires are too high, because the platforms and towers have electric wires, and because the towers they can climb down are in the yards. The orangutans are most comfortable along familiar pathways and living spaces such as their enclosures and the O Line. All of their needs are met in this area so there is no reason for them to search for a new territory. Also, the animals feel more comfortable in their home environments of the Great Ape House and Think Tank.

Has anyone ever escaped?

Yes, three animals have passed over the electrical barrier and climbed down the towers. In 1994, during the design test phase of the O Line, Azy, an adult male, traveled over to the one connected tower and, after receiving a shock on a hand and foot, climbed down the tower. He was sedated on Olmsted Walk, and returned to his enclosure. Over the next nine years at the Zoo, Azy never again choose to travel the O Line Alterations were made to Towers 2 through 7 to improve the effectiveness of the electrification ststem.

In 2002 Junior, an adult male, traveled for the first time after watching the system in use for eight years. Unfortunately, although he traveled correctly, his size and long draping hair brought him in contact with the electric wires, as he arrived at each tower. After successfully traveling to his seventh tower, he climbed down the tower to avoid another shock. He was sedated and returned to the Great Ape House. The O Line towers and cables were subsequently raised an additional five feet to give the large males more room to travel safely. They are currently 50 feet (16.6 meters) high.

In 2005, Kyle, a young male orangutan was being acclimated to the O Line system soon after his arrival at the Zoo. On his first trip he crossed to his first tower, misplaced a foot, and was shocked. He then climbed down the tower and jumped into the Ape House yard.

Each one of the escapes off of the O Line was an orangutan that was traveling on the cables for the first time. We have not had an orangutan escape off of the O Line twice. When introducing new orangutans to the O Line system, precautions are made for the safety of the animals and Zoo staff and visitors. Introductions to the O Line are made in the early morning when the zoo is not crowded, with closure of the surrounding area, and all great ape keeper staff available in case a problem arises.

What if they go to the bathroom while they are over people?

They do, so staff and volunteers tell visitors to look up to see if an animal is directly above them and if so, to move! The O Line crossings are highlighted by the patterned pavers on Olmsted Walk and a painted zone in front of Think Tank, designating the “splash or splatter zone” when orangutans are traveling overhead. When viewing the orangutans traveling the O Line, we encourage visitors to stand clear of these areas to avoid any messy mishaps. The animal care staff respond to any required cleanups. If a visitor is ever hit, the staff are prepared to assist.