>>5009167
>>5009169
>>5009306
>>5009386

The brightly vivid colouration in the boiling pools is caused by microbial mats. Literally piles upon piles of microbes so thick they form a visible layer of yellow, red, slime.
The bison will be boiled down into mush and that much will practically disappear before ones' eyes as it's eaten voraciously by the microbes. In such extreme conditions an event like this is an extravagant feast.