Humans have looked at animals as dinner since, well, we became humans. And before the grocery store separated us from what our food actually looks like, hunting was the primary method for getting a boar or fowl from the forest to the spit or chopping block.

But around 15,000 years ago, humans began the process of raising certain creatures to stay close, starting with canines, who were domesticated to aid in hunting down the other, still-wild meat sources. Domestication of animals like pigs, goats, and sheep soon followed, and that naturally made it much easier to attain diets richer in animals proteins, from meat to animal products like eggs and dairy. (You can learn some fascinating facts about