As part of our ongoing Hardcore Science Interview series, we interviewed the American Natural History Museum's invertebrate zoology curator, Mark Siddall. A world-renowned expert on leeches, he told us about how these strange creatures reproduce by inseminating each other (yes, they are hermaphrodites) . . . and how to hunt them without losing too much blood. You'll never look at a leech quite the same way again.

This interview was conducted by Annalee Newitz, and directed by Matt Toder. Many thanks to the AMNH. Look for our other videos in the Hardcore Science Interview series, and visit the AMNH to see their latest exhibitions.