What are the differences between pig and hog? The writer of this article wrote them consecutively, separated by only a comma. Searching Google images result in the same type of animal. The differences between pig and boar are clear though.
Actually, in current usage, "hog" and "pig" means pretty much the same, although there is a slight difference in semantics among pig breeders or famers:
The words "swine," "hogs," and "pigs" refer to animals of the porcine family or pig family. The term swine can also refer to the pig family in a general way, and "pig" can be used in referencing young animals. "Hog" will generally refer to animals at or nearing market weight or finished for market.
So, "hogs" referred to grown-up pigs. Why, in the first place, was two different words? It seems that, from Wiktionary, "hog" used to have a slightly different meaning:
Hog" originally meant a castrated male pig. (Compare "hoggett" for a castrated male sheep.)
But that usage is no longer common. Kind of Archaic.
I can't say I read the article thoroughly, but it seems, that the author uses hog as a synonym for feral pig as opposed to domestic pig which is either called that or simply pig.
**According to this Article
In the United States, the term "pig" refers to a younger domesticated swine weighing less than 120 pounds (50 kilograms), and the term "hog" refers to older swine weighing more than 120 lbs. In Great Britain all domesticated swine are referred to as pigs.