Pigs are an invasive species in the Americas. Pigs originally evolved from wild boars which were over time domesticated by man. Wild boars were found through out much of Europe and Asia so when settlers came to the Americas they brought domestic pics with them. The main physical difference between pigs and peccaries are the tusks. Peccaries have short tusks which are straight where pigs have long tusks that curve around in on themselves. This is a photo of a feral or wild pig. Pigs that get loose or are let go can live out in the wild where they often compete for found with peccaries and other endemic species. I photographed this feral pig at the Laguna Atascosa NWR in south Texas.