Researchers observed an unusual act of wound self-treatment in a Sumatran orangutan named Rakus.
After receiving a facial injury from sparring, Rakus picked leaves from the plant Fibraurea tinctoria, known for anti-inflammatory properties.
He chewed the leaves into a paste and applied it directly to his wound for several minutes, covering it entirely.
Over the next few days, the natural bandage prevented infection and the injury healed completely.
This was the first observation of an orangutan actively using plant properties to treat an open wound.
Researchers believe Rakus may have discovered the plant’s benefits accidentally during feeding or learned it from migrating relatives.
“Orangutans at [Suaq] rarely eat the plant,” study senior author Caroline Schuppli said. “However, individuals may accidentally touch their wounds while feeding on this plant and thus unintentionally apply the plant’s juice to their wounds. As Fibraurea tinctoria has potent analgesic effects, individuals may feel an immediate pain release, causing them to repeat the behavior several times.”
The behavior raises questions about a shared evolutionary ancestry between great apes and humans for recognizing medically useful substances.
It provides insight into orangutans’ cognitive abilities and potential transmission of medicinal plant knowledge.
