You open your eyes and find yourself sitting across from this man. He introduces himself: Mark Siddall of the American Museum of Natural History. Yes, those are leeches on his arm, 12 of them. But those "fingerlings" are like minnows to the sturgeon Mark will be seeking out momentarily, thigh-deep in a nearby swamp, with you at his side. As he smiles and guides you off the verandah, you consider what you'd urgently like to know about the giant Amazonian leech, the near-mythic creature he's seeking. How big? Well, it's the world's largest bloodsucking leech—by a good bit. Any other questions?—Peter Tyson