Not a myth. They are down around Mesquite, NV and mostly along the river. I wouldn't say the numbers are high and they are difficult to locate and hunt due to the thick vegetation along the river. The other hard part is getting permission from farmers to hunt their land. I use to have connections with the Hafen ranch below the golf course. He would occasionally run into hogs in his fields at night while changing the water in the fields and had several shoulder mounts in his house from hogs he killed on his place. How the Hogs got there is the myth. A lot of different stories about how they got there. Some even claim that they have ranged up river as far as Caliente.