Seahorses and pipefish may be the world’s most unconventional dads. They’re the only vertebrates capable of male pregnancy—meaning they fertilize and carry a female’s eggs to term. The tiny fish aren’t simply trying to score points with their undersea mates; in the video above, courtesy of online science series The Macroscope, Brooklyn College professor Tony Wilson explores the ecological advantages of being an “expecting” seahorse papa. He also explains how the males nurture their brood, and reveals the surprising link between seahorse pregnancy and mammalian pregnancy.

[h/t The Kid Should See This]

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