Scientists don’t know much about how our acidic taste evolved.

Enter Rob Dunn. The North Carolina State University ecologist and his collaborators have spent years scanning the scientific literature in search of an answer. In a paper published [recently] in the Proceedings of the Royal Society B, the team reports some clues. Science chatted with Dunn about how, and why, humans like to pucker up.

Q: Sweet taste gives us a reward for energy, and bitter alerts us to potential poisons. Why might we have evolved a taste for sour?

A: Sour taste was likely present in ancient fish—they’re the earliest vertebrate animals that we know can sense sour. The origin in fish was likely not to taste food with their mouths, but to sense acidity in the ocean—basically fish “tasting” with the outside of their body.

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Q: So how did sour detection become paired to eating and drinking?

A: We’ve lost the ability to produce vitamin C, or ascorbic acid, and liking acidic foods might be a way for us and other primate species to be reminded to ingest it. Another argument is that ancient primates ate way more fermented foods than we recognize. One way to tell if rotting fruits are safe is if they’re acidic.

This is an excerpt. Read the original post here.