What did they do with buffalo tongues?
In respect to this, why were bison hunted for their tongues?
They were hunted for their skins and tongues with the rest of the animal left behind to decay on the ground. After the animals rotted, their bones were collected and shipped back east in large quantities. Due to the roaming behavior of bison, their mass destruction came with relative ease to hunters.
Similarly, you may ask, what did they do with all the buffalo hides?
Indians of the northern Plains wore buffalo hides for both practical and ceremonial purposes. They wore buffalo hides in winter, with the fur on the inside for warmth. When people were sick, they often wore a hide painted with symbols to hasten healing. Men usually wore hides that told a story in pictures.
The Plains Indians were not the only ones who valued the American buffalo. Hides were worth good money back east, where they were used as belts for factory machines and as fashionable robes and rugs. Settlers' livestock carried diseases that destroyed buffalo herds.