A new study finds that pigs often outsmart dogs in IQ tests and share a number of traits with classically intelligent species, such as chimps, dolphins, and elephants. While this sort of ranking has often been bandied about, and a definitive Intelligence Ranking would be nigh impossible to generate, there is absolutely no question that pigs can think and act in nuanced, emotional, complex ways that rival -- or exceed-- many species we consider to be intelligent.

Researchers reviewed many studies, each of which often focus on a single cognitive trait, to get a better picture of where pigs stand relative to other animals. Pigs have marvelous long-term memories, excel at mathematical and spatial tests, can understand simple symbolic language, love playing and engage in nuanced social relationships with many individuals, cooperate, understand how to use mirrors to find hidden objects, and exhibit empathy.

This vaults pigs to the unpleasant position of being one of the most poorly treated and smartest animals consumed by humans for meat. If you are an ethical eater, pigs are an obvious choice to remove from your diet.