|MadSci Network: Development|
Hello Ashley, Thank you for your question! I'm always happy to talk about snails and hope I can answer your question. First of all, snails are not asexual. In fact, I can't think of any asexual molluscs at all (snails are gastropod molluscs). I'll address the sexuality of certain snails in a bit. The answer to your question depends on the kind of snail you're talking about. I'm a marine biologist, so most of the snails I'm used to thinking about are marine snails. Many marine snails are free-spawners. That means that male and female snails shed their gametes into the seawater, and fertilization and development occur in the water column. So you couldn't really say that these snails "have a baby," since the parents have nothing to do with development of the baby snails at all. But if you're interested, the length of development from zygote (fertilized egg) to juvenile snail is anywhere from a few weeks to a few months, depending on the species. Other marine snails are not free-spawners. Instead, males either copulate with females or shed their sperm into the water, and females lay large egg masses attached to rocks, shells, and other surfaces. These eggs typically hatch as late larval stages or as tiny juvenile snails. Development time for these snails is usually shorter than for the free-spawners. But I have a gut feeling that the snail you bought is either a freshwater or a terrestrial snail. These snails are almost always hermaphrodites, which means that an individual snail functions both as males and as females. This mode of sexuality is common in marine snails, too. The benefit of hermaphroditism is that it allows an individual to mate with any other member of its species, instead of having to wait for one of the opposite sex. Some hermaphrodites can even use their own sperm to fertilize their eggs, so they don't have to wait for any mate at all! Free-spawning obviously doesn't work on land, so terrestrial snails are copulators and egg-layers. Freshwater snails, to my knowledge, are also egg-layers. Since these snails are hermaphrodites, they can copulate and exchange sperm with any other individuals of their species. So your snail may have been "pregnant" when you bought it. I'd say that if he/she was indeed pregnant, it should lay eggs in a couple of weeks, and the babies should hatch shortly after. [If your snail is in an aquarium, look for little jellylike blobs attached to the aquarium glass - these are the snail's eggs. They might look like little bubbles stuck to the glass.] If you don't see babies after a few months, chances are your snail wasn't pregnant already, and unless it's one of the self-fertile hermaphrodites, it won't make babies by itself. If you do see babies, then you'll know either that your snail was pregnant, or that is a self-fertile hermaphrodite. Which is kinda cool, if you think about it. Good luck! Allison J. Gong Mad Scientist References: Strathmann, M.F. 1987. Reproduction and Development of Marine Invertebrates of the Northern Pacific Coast. University of Washington Press, Seattle and London. Pearse and Buchsbaum. 1987. Living Invertebrates. Blackwell Scientific Publications, Pacific Grove.
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