It's a thrilling sight to see the orangutans traveling on
the Zoo's Orangutan Transport System, or O Line. The O Line gives the orangs freedom of movement, an expanded living area, and choice of location.
Orangutans are brachiators, which means they can swing hand
over hand from branch to branch. Kiko, a younger male, often
demonstrates this form of locomotion on the O Line. The other orangutans,
however, usually walk or shuffle along the cables, holding
on with two or more limbs.
Frequently
Asked O Line Questions
When Think Tank curators were deciding which animals to include in the exhibit, they wanted to include orangutans but were faced with a number of challenges. The exhibit space at Think Tank was not big enough to permanently house a large number of orangutans. Because of the building's status as a historic landmark, major renovation to expand the exhibit space was not an option. Additionally, the orangutans' permanent home, the Great Ape House, is some 490 feet (149.5 m) from the new exhibit.
The solution? Let the animals move themselves! Curators designed the world's first Orangutan Transport System (OTS), a system of towers and cables that allows the animals to move between the two buildings.
The Orangutan Transport System, or O Line, consists of eight, 50-foot-high (12.2 m) towers connected by plastic-coated, steel cables. At the lowest point, the cables are about 35 feet (10.7 m) off the ground. The entire distance of the O Line is about 490 feet (149.5 m). Tower 1 is in the outdoor orangutan yard at the Great Ape House. Tower 8 is in the outdoor orangutan yard at Think Tank. The towers in between are outside the confines of the animal yards, and the O Line crosses Olmsted Walk twice.
The O Line is open to any orangutan in the yard at Think Tank or at the Great Ape House. The towers in the yards (1 and 8) are fully open for climbing. Towers 2 through 7 have only the top platform open to the orangutans. There are wide wire "skirts" below these platforms to keep the orangutans from climbing down.
The skirts and surrounding grid "collars" are electrically charged to keep the orangutans from climbing down (and visitors from climbing up) the towers. The charge in the system is just enough to give an orangutan a sharp sting without causing injury. Each tower is connected to an alarm system that the Animal Care staff can see and hear to alert them of any problems with the line. The electric supply to the towers is connected to an emergency generator, which triggers the alarm when called into use.
A keeper monitors the orangutans whenever they have access to the towers (usually between 10 a.m. and 2 p.m.). The orangutans are given access to the O Line when the temperature is above 40 degrees Fahrenheit without strong winds or precipitation.
Since orangutans are brachiators and can swing hand over hand
from branch to branch, some orangutans use this method to
cross the O Line. However, most of them walk or shuffle along
the cables, holding on with two or more limbs. In the wild,
this movement distributes the animal's weight among several
branches. Not all the orangutans that have access to the
O Line have used it.
