Ground squirrels, they are sometimes called "Dak Rats" or "gophers",
Gophers create a large community of tunnels with large mounds of dirt at their entrances, frequently referred to as "towns".
Adult gophers will frequently stand watch at the entrance to a tunnel and whistle when predators are spotted, causing all the other gophers to run for the safety of the tunnels.
A gopher town can easily spread to take over large sections of prairie or mountain meadows and may have a population in the thousands.
Farmers usually kill them because they destroy their crops.