A foxtail is a spikelet or spikelet cluster of a grass, that serves to disperse its seeds as a unit. Thus, the foxtail is a type of diaspore or plant dispersal unit. Some grasses that produce a foxtail are themselves called "foxtail", also "spear grass". They can become a health hazard for dogs and other domestic animals, and a nuisance for people. Foxtail Grass is most commonly found in the Great Plains where bison and other native animals graze on it. Fires started by lightning can burn down Foxtail Grass, but the grass has roots underground that allow it to grow back.