I've never seen such fat prairie dogs !
I think the seeds and prairie grasses they eat become extra rich in nutrients in the fall months so that the animals can put on extra fat for the winter.
"So don't worry about these things, What will we eat? What will we drink? What will we wear? For the pagans run after all these things, and your heavenly Father knows that you need them. But seek first His kingdom and His righteousness, and all these things will be given to you as well."