"How do we find these
leeches?" No worries there—they find you. You're the bait. You can't set traps for leeches, so the standard method is to bare your legs and wade out into its domain, like Mark is doing here. He's bending over because it's hard to see approaching leeches. Their skin is a deep green-brown and the water is the color of dark tea and your feet stir up the mud. But don't worry, they can sense you from as far away as a ripple will travel, Mark says, and if they're near enough, they'll either undulate over like a living ribbon or they'll "inchworm" along surface plants or the bottom using their head as a second foot. They don't have eyes per se, but their eyespots are so sensitive that if you wave your hand across their field of vision, they'll track the movement. And they can sense your shadow. So there's little chance they won't find you.