In 2006, a study published in the journal Biology Letters described a fossil unlike any ever seen before. It captured a prehistoric reptile that lived around 125 million years ago. That, in itself, wasn’t terribly surprising, but the fact that it had two heads really, really was. The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.

Bicephalism describes a quirk in animal development that results in an individual with two heads. We’ve seen remarkable examples of it in wild animals, such as this southern black racer snake that was found to have independent brains that disagreed with each other.

As we know, fossilization is a treatment only granted to a select few of the animals that have ever lived on Earth. You’ve got to die in ju

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