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| The Banana Slug. Go Santa Cruz! |
So friend asked me a question about last weeks post: whats the difference between snails and slugs anyway?
Not only is this a great question, but it has inspired me to start a new series of posts called Whats the Difference, where I'll be addressing the differences (and similarities) between commonly mixed up animals and features. So if you've ever been confused about the difference between apes and monkeys, antlers and horns, whales and dolphins, or any one of the numerous other pairs that seem like basically the same thing. If you have a particular pair of things you want to know about, please let me know. Also, "What's the difference"is admittedly a weak name... so I'm taking suggestions!
Todays I'll cover the question that started this, what is the difference between snails and slugs?
Luckily this is a pretty easy distinction. Snails have shells, slugs don't.
Unimpressed? I am sorry to disappoint, but they are very similar in almost every other way. Both snails and slugs are molluscs, which meaning they belong to the phylum Mollusca along with all sorts of other cool critters like mussels, chitons and octopuses/ octopi (yes, both are correct).
But why would a slug ever give up it's shell? Well, there are the obvious disadvantages to the snail shell in terms of body's *ahem* orientation (see last post). But even more than that, slugs have found many ways around the disadvantages of lacking a shell without actually investing in making one. For one thing, slugs live only in humid climates, and even then only come out at night or when it's is especially wet out. Water is vital, and without a shell to protect them from some of that water loss, snails deal with it by choosing their environments carefully. Slugs also don't have to worry about collecting calcium. Calcium is one of the primary elements in building a snail shell, and for marine snails this is not a problem. Calcium is one of the many "salts" that make sea water salty, and if you are making a shell from calcium being surrounded by it makes your job considerably easier. But in a terrestrial environment calcium can be a lot harder to come by. Terrestrial slugs have tried to make the best of a bad situation and simply given up on calcium shells altogether.
However, there are marine slugs as well, meaning that finding calcium might not be the biggest driving factor behind shell loss. Many slugs have taken up burrowing in sediment in order to escape the heat of the day or to find food. As one might imagine, a large coiled shell is rather an inconvenience when burrowing, and it is much more convenient to go without.
Slugs are also not without their own forms of protection. Though they lack a shell, slugs depend greatly on the chemicals in their slime. Slugs are sticky, slimy, and taste terrible. Although different from the protection of a hard shell, the chemicals are never-the-less effective, as some slugs, like the banana slug (GO SLUGS!) have no major natural predators.
So this turned into a post about slugs more than about the difference between slugs and snails, but I think you get my point that there are really just a couple of major differences: Slugs don't have a shell, and a snail is ass-backwards.
Sources I trusted were surprisingly hard to find, but here are the ones I used:
http://www.andrewgray.com/essays/molluscs.htm
http://www.molluscs.at/gastropoda/index.html
The picture is my own
But why would a slug ever give up it's shell? Well, there are the obvious disadvantages to the snail shell in terms of body's *ahem* orientation (see last post). But even more than that, slugs have found many ways around the disadvantages of lacking a shell without actually investing in making one. For one thing, slugs live only in humid climates, and even then only come out at night or when it's is especially wet out. Water is vital, and without a shell to protect them from some of that water loss, snails deal with it by choosing their environments carefully. Slugs also don't have to worry about collecting calcium. Calcium is one of the primary elements in building a snail shell, and for marine snails this is not a problem. Calcium is one of the many "salts" that make sea water salty, and if you are making a shell from calcium being surrounded by it makes your job considerably easier. But in a terrestrial environment calcium can be a lot harder to come by. Terrestrial slugs have tried to make the best of a bad situation and simply given up on calcium shells altogether.
However, there are marine slugs as well, meaning that finding calcium might not be the biggest driving factor behind shell loss. Many slugs have taken up burrowing in sediment in order to escape the heat of the day or to find food. As one might imagine, a large coiled shell is rather an inconvenience when burrowing, and it is much more convenient to go without.
Slugs are also not without their own forms of protection. Though they lack a shell, slugs depend greatly on the chemicals in their slime. Slugs are sticky, slimy, and taste terrible. Although different from the protection of a hard shell, the chemicals are never-the-less effective, as some slugs, like the banana slug (GO SLUGS!) have no major natural predators.
So this turned into a post about slugs more than about the difference between slugs and snails, but I think you get my point that there are really just a couple of major differences: Slugs don't have a shell, and a snail is ass-backwards.
Sources I trusted were surprisingly hard to find, but here are the ones I used:
http://www.andrewgray.com/essays/molluscs.htm
http://www.molluscs.at/gastropoda/index.html
The picture is my own
Great job Ian and thank you for the research on this subject �� Please be mindful to review your work before posting for errors...I share this not as a critic but to be helpful. I am very impressed with your work and will be on the lookout for more of your posts...May God bless each of your endeavours & give you much success and prosperity as you pursue your goals��
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