The Arumbayas are a pre-Colombian indigenous people living in the jungles of South America (along the fictional River Coliflor). One thing that was special was that people everywhere feared them and thought of them as savage people. They first appeared in The Broken Ear, where while investigating the theft of an Arumbaya fetish, Tintin and Snowy venture into the San Theodoran jungle. Despite being informed of their reputation for being vicious savages, the Arumbayas prove to be relatively civil when Tintin encounters them. The bad reputation the have may be due to the actions of their near-neighbors and rivals, the Rumbabas, who behead any strangers who pass their way, shrink the heads down and put them on display.
The Arumbayas also knew of some form of mining, and had a hidden collection of gemstones including the revered Heart of the Jungle, an ancient gemstone that is believed to have magical healing powers. A.J. Walker was the first European to study the Arumbayas in the mid-nineteenth century. It was he who brought the Idol of the Broken Ear back to Europe. During his expedition, Walker was shown the gem after gaining the trust of the Arumbayas. Walker's local guide, Lopez subsequently stole the gem and hid it inside the Idol of the Broken Ear, ironically a gift to Walker, to thank him for his vow of silence. The Arumbayas gave chase to Walker's party after learning of its theft resulting in Lopez's abandonment of the idol, leaving Walker with the idol, who would bring it to Europe.
Dr Ridgewell, a British explorer, lives with the Arumbayas. He finds their society fascinating and seeks to learn from them. Ridgewel in kind has also taught the Arumbayas in modern ways too, such as the game of golf and warns them of the perils of alcohol consumption, however, they had trouble adapting to the modern ways. He chose to stay permenantly, leading local San Theodorans (such as Don José Trujillo) to believe he was killed by the Arumbayas. The Arumbayas would also later feature in Tintin and the Picaros, where they aid General Alcazar's forces, the Los Picaros against General Tapioca's dictatorship. Their fate after Alcazar's coup is unknown.