![]() Research on the rasping tongue of land snails (Video: Universität Hamburg) That corresponds to almost 3300 of the total of around 22,000 teeth. “We counted the number of teeth on the radula and were able to see through video recordings that only about 15 percent of the tongue is actually used to scratch the food. Only the outer tips of the radula teeth touched the ground. The camera recordings revealed: “When the snail eats, it tightens the radula like a band so that the teeth stick out a little and can be used for scratching,” reports Krings. A camera also recorded the movements of the radula from below. “It was relatively difficult to develop the experimental set-up because we had to make sure that nothing else than the radula touched the sensor from the screw,” says Krings. During the experiments, they applied a feed paste made from flour and carrot juice to a transparent acrylic plate in which a tiny force sensor was embedded. “We wanted to see what snails can actually do with their teeth,” explains Krings. How is that possible? To find out, Wencke Krings from the Center for Natural History at the University of Hamburg and her colleagues examined the functioning and the power of the radula of spotted garden snails (Cornu aspersum) in more detail. Nevertheless, the animals can easily eat even hard food with their radula. The interesting thing about it: The snail’s teeth are relatively soft – in a Roman snail they are about the hardness of wood. ![]() There it is pressed against the rigid jaw, which, for example, tears leaves and other larger parts of plants. Like a small bucket wheel excavator, the toothed tongue then transports the feed into the mouth of the screw. Then she pulls her tongue back and rubs the food off the ground with her radula teeth. When a snail eats, it first pushes its radula forward out of its mouth and presses part of its teeth onto the food. The mouth tool consists of a chitin band, which is covered with thousands of tiny teeth in longitudinal and transverse rows. The secret of their success lies in their ability to pick up both soft and very hard food with their rasping tongue. Snails colonize almost all habitats on our planet – from the deep sea to deserts to high mountains. The radula teeth therefore act on the subsurface with a pressure of 4700 bar – that is as much as with an industrial waterjet cutter. ![]() ![]() The special thing about it: Although the individual teeth are rather soft, the tongue is surprisingly strong, as experiments have shown. Do these molluscs have something like teeth in their mouths? In a way, yes, and on the tongue: with her toothy radula cut, chop and shovel your food down your throat. They also eat very hard food – snails seem to be able to “bite” surprisingly hard. ![]()
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