This male sumatran orangutan is Raku: he got a wound on his right cheek. Scientists were surprised to spot him applying a medicinal plant on his face: akar kuning (Fibranaurea tinctoria), a type of climbing vine that acts as an analgesic.

After about 8 days he applied the chewed stems and leaves of the plant, the wound began to heal and in approximately a month he completely recovered.

This series of observations undoubtedly constitutes the conclusive proof of the level of ingenuity that these majestic animals have.