Welcome to brain Stuff production of I Heart Radio. Hey brain Stuff, Lauren vogle bomb here with a classic episode for you. This one deals with the exoskeletal science of one of my personal favorite animals, snails. I keep some aquatic snails as pets and watching them hatch and grow is absolutely wild, if not exactly fast going. Here's how it works, Hey brain Stuff, Lauren voge bomb here. Snails
are very attached to their shells. Literally, these slow moving mollusks grow protective shells to which they are physically connected. Eviction means death. No snail can survive being torn away from its private calcified fortress. But how exactly do snails shells develop and what sets them apart from other types of animal armor. Before we get to that a bit of snail one oh one, the total number of snail
species could be as high as forty three thou. Most of us are familiar with the land based varieties or those that live in ponds, but marine snails also exist. And when it comes to procreation, certain species reproduce sexually, while others are self fertilizing hermaphrodites. Whatever gets the job done right. They all do have one thing in common,
though snails all hatch from eggs. Generally, the parents lay these eggs in loose soil or affix them to rocks, though a few species are over viviparous, meaning their eggs hatch inside the mother's body. The newborns then squirm out and face the world. But this brings us back to that question about the shell. It's during the gestation period that a snail's shell begins to form, and here's where the mantle comes in. This is a crucial organ possessed
by molluscs such as snails. Its function is making and developing shells. Calcium carbonate is the primary ingredient in snail shells. Those small amounts of protein also go into the mix, so in order to build these shells, the mantle creates an electric current that helps the organism push calcium ions into the right places. Before hatching, a baby snail grows a protoconch, the first component of its shell. Once our little snail leaves the egg, healthy eating becomes a priority.
The mantle will require additional calcium to strengthen and expand the shell. Instinct compels newborn snails to devour what's left of the calcium rich egg that they've just escaped, and thus begins a lifelong habit. Snails of all ages and sizes need to keep eating foods that are high in calcium. This is one reason why snails are so often considered pests. A few of them like to chow down on spinach, broccoli, turnip, and other calcium loaded crops. They can also get their
calcium fixed by swallowing soil or gnawing on limestone. That protoconch comes with a small opening or mouth. The mantle organ adds new layers of calcium, carbonate and proteins to the mouth from below. As that new material hardens at the mouth, the shell grows, Spiraling coils form around the protoconch, which gradually spins around and around, becoming the apex, or
uppermost tip of the snails widening shell. Depending on the species, the protoconch will either remain there permanently or break off at some point. Snail shells always coiled to the right or to the left. That's another thing that varies from species to species. Most snails possess right word pointing shells, but there are a few whose shells orient towards the left, and in some species. These shells can coil in either direction. If you were to cut open a snail shell, you've
noticed several main layers in the cross section. At the surface, there's the peiostracum, a thin outer layer usually made with organic material. Below that, you've got a layer of hard calcium sitting atop a blanket of noker. That's a resilient composite material better known as mother of pearl. One thing you won't find, however, is a network of nerves or
blood vessels. Turtle shells, meanwhile, contain both. In most cases, the shells we find in these much adored reptiles are really networks of modified bones like ribs, vertebra, and pelvic elements that have been fused together and covered by hard plates. When a turtle shell gets cracked, the body dispatches cells to try and repair the damage. Snails have a different method for fixing cracks. Calcium and protein secretions from their mantles can be used to help strengthen the damaged areas.
Of course, having a shell, even one that can heal itself, does not guarantee safety. Ironically, a lot of nesting birds like to eat snails because of their protective shells and the calcium that they contain. To keep one step ahead of predators, Many snails have seriously up to their self defense game. For example, the deep sea species Chrystomalin squareferum is covered in iron sulfide, giving the entire animal a
strange metallic appearance and acting basically like battle armor. In fact, researchers have looked into the possibility of using this animal's amazing exterior to develop better armor for human soldiers. Today's episode is based on the article how does Snails get their shells? On how stuff works dot Com, written by Mark Mancini. Brain Stuff is production of I Heart Radio in partnership with how stuff works dot Com, and it's
produced by Tyler clay Or. More podcasts my heart Radio, visit the I heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows,