we learned about them in class: they can be found in las vegas ..on the outskirts only very very small as they die/get eatten by other preditors. And you can't feel them gnaw on you; they have a venom that numbs you, and they eat your flesh ...but not huge holes as they are little ...and mostly dead when found here.
a guy I rped with was in the military and said they are a major pain.