The target is Neesia, a woody fruit whose split capsule is packed with fat-rich seeds surrounded by irritating hairs. A Suaq orangutan selects a twig, strips its leaves, sometimes shortens it, and uses it to loosen seeds without touching the hairs. The same basic probe is applied to honey and insects in hollow trunks, with a slightly different grip.
Suaq is unusually crowded for orangutans, with high fruit availability supporting more contact between individuals and more tolerated close watching by youngsters. That combination of opportunity to observe and a payoff worth copying is the standard explanation for why the technique concentrates there.
Sumatran orangutans also modify sound. They strip leaves and hold them at the mouth while making a kiss-squeak alarm, which lowers the call's frequency. Whether this functions to exaggerate apparent body size is a plausible but not settled interpretation.