So one presumes that both copulating snails are eager to get that part done. Tough Love For their experiment, study leader Kazuki Kimura , a biologist at Tohoku University in Japan, and colleagues compared the number of egg clutches with rates of longevity in captive populations of Bradybaena pellucida, a species of land snail native to Japan. Answer 2: Secret of the Slime. They glisten as they move, and because they are snails, everything happens very slowly. By waving their upper tentacles in the air—smelling—and tapping their lower ones on the ground—tasting—they pick up on the gooey trails of potential partners. Professor David George Haskell, a Tennessee biologist, once squatted down on a patch of forest floor and watched what you just saw in that video—a snail couple going at it—except with a magnifying glass and only a few feet from the action. But some snails have both eggs and sperm in their bodies, so sometimes the sperm in the snail fertilize the eggs in the same snail. No one wants its precious eggs fertilized by a sick dad, so the receiving snail might lock its partner out of its opening while also trying to penetrate it. What we forget, being humans, is that there are so many ways to flirt, to combine, to make babies—and the world is full of wildly different ways to woo. That is, if darts allow a snail to father many more young, a few less isn't a huge deal. Scale it up to human size and the love dart would be the equivalent of a inch knife, according to Koene. By using dyes to follow their movement, cells from one stage of embryonic development can be traced to different locations at later stages. What makes Crepidula interesting is although they make both sperm and egg cells in the same individual, they function as either sex and not both simultaneously. Click Here to return to the search form. If she were a female walkingstick bug she might insert her hypodermic proboscis delicately into my neck and inject me with a rich hormonal sedative before attaching her egg sac to my thoracic undercarriage, and if I were a young chimpanzee I would break off a nearby tree limb and smash all the windows in the plaza jewelry stores.