The kids' favorite animal of the whole trip to South Dakota were the prairie dogs. They named this one Grassy.
This fat bastage was christened Pipsqueak.
I'm not sure if these ones got named.
Prairie dogs are apparently a keystone species, they keep mesquite and brushy stuff from taking over the grasslands. I was hoping to see some of the higher on the foodchain associated species like Burrowing Owl or Black-footed Ferret but no such luck, closest I could come was this (I'm guessing Thirteen-lined) ground-squirrel