Of all domesticated animals, pigs are the most similar to us and we share a long history.

At first glance, pigs and humans don’t seem to have a lot in common. But take a closer look and the similarities are hard to miss.

For starters, let’s look at our similar digestive systems.

Pigs and humans are both omnivores, meaning we can both basically eat anything. We share a stomach that breaks down proteins, a small intestine that absorbs sugar and a colon that absorbs all the water. But the similarities don’t end there.

Just consider our teeth.

In 1922, a fossil hunter dug up a 10-million-year-old tooth in Nebraska. It eventually found its way to Henry Fairfield Osborn, former director of New York’s Natural History Museum. Upon analysis, Osborn concluded that it was a human tooth from the first human-like ape, which he dubbed the Nebraska Man. But Osborn was mistaken: the tooth actually came from an ancient and extinct pig-like creature.

And when we look back to ancient times, we find that, as humans started settling down in around 10,000 BC, they brought domesticated pigs along with them.

Humans and pigs have always had a strong relationship and settling into communities made it even stronger. At the sites of several ancient villages around the world, remains of both human and pig bones have been found.

At Hallan Cemi, a famous site in Turkey, researchers discovered that the bones all came from pigs less than one year old, suggesting that they were slaughtered for food.

But a closer look at early domesticated pigs suggests that they weren’t just a source of meat but were also used to keep the villages clean by eating leftovers and garbage.

Evidence shows that early humans would normally leave a site when the garbage levels reached a critical mass. With pigs functioning as ambulant garbage-disposal units, however, settlements became more permanent.

As we’ll see, though, pigs were both valued and avoided for the same reason.