MadSci Network: Development

Re: How long does it take a snail to have a baby?

Date: Sun Jan 21 23:15:31 2001
Posted By: Allison J. Gong, Graduate student
Area of science: Development
ID: 979778348.Dv

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


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.

Current Queue | Current Queue for Development | Development archives

Try the links in the MadSci Library for more information on Development.

MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci

MadSci Network,
© 1995-2001. All rights reserved.