I understand that snails are born in eggs, but how do they get that massive shell and they aren’t multicolored? Like hermit crabs get different shells as they grow.. right?
In: Planetary Science
Snails slowly grow their shells, which is why it gets the significant shape it has, the shell itself made of something similar to keratin and is basically the same as a nail or a horn.
Hermit crabs dont grow their shells themselves, as they arent gastropods like snails. From an evolutionary standpoint they found their niche in using older shells made from marine gastropods to protect themselves.
Snails, like clams and oysters, grow their shell from minerals they extract from their food and water (primarily calcium and carbon, as their shells are mostly calcium carbonate). Each species grows their shells in a particular pattern, and plenty of them are in fact multicolored. There are many different shapes of snail shell – conch shells look like trumpets, turban snails have cylindrical shells, certain *Astrea* snails have shells that look like ninja stars, ramshorn snails have shells that curl up like a ram’s horn. Some shells have tiger striping, some are speckled, some are bright and shiny, some look like marble. It’s all based on the individual species.
Hermit crabs are a completely different group of animals; they’re crustaceans, with an exoskeleton composed of chitin. However, they’ve evolved to steal snail shells to cover their soft lower bodies; there are enough snails out there that it’s not hard for hermits to find a nice shell to live in. Over the course of their life, they will change shells multiple time, usually as they outgrow whatever shell they’re currently living in. If they can’t find a suitable empty shell, they’ll attack and kill a living snail to steal its shell.
Snails grow their shells, as do most creatures with shells. They are made of calcium carbonate, which is a very simple molecule that they just kind of extrude. The shells are striped because of impurities that can get caught up in the next layer of shell.
Hermit crabs are unique because they find shells from other creatures. As they grow, they need to find a new shell that fits them, since they are not growing their own shell.
The snail slowly grows its shell from the base, as new portions of the shell are formed, the older parts are pushed upward which forms the distinctive spiral shape.
As for what they are made up, its primarily calcium carbonate with some organic proteins to help seal everything together. Land snails get it from the food they eat, aquatic snails in both marine and freshwater can get it from food or from the water if the water is rich in the stuff. Most other shells, particularly in aquatic animals, are also made of calcium carbonate, such as clam shells, barnacles, or coral.
Hermit crabs are scavengers of shells, taking abandoned shells left when a snail dies for itself. The backside of a hermit crab is very soft and flexible, which allows them to pick up a shell and gain a much stronger defense than normal crabs, at the cost of being more vulnerable without it and having to find an upgrade as they grow older and larger.
Latest Answers