Wednesday, June 13, 2012

Up Close at the Touch Tank

The Touch Tank is a marvelous--and popular!--place where our Museum Guests can get up close and personal with several aquatic animals native to the Chesapeake Bay--and can even touch some of them with the assistance of our very dedicated volunteers.  A special thanks to volunteers Carolyn Jablow, Carly Cook, and Laurel Deffenbaugh who so ably assisted me as I took the photos below.  The first photo is a close up of a claw--do you know what it belongs to?
These animals use empty whelk or snail shells as their home--making them sort of like mobile tanks!  When tucked up into the shell, this animal will flatten its claws at the opening of the shell like a trap door:
But when it comes out, you can see that it's a hermit crab:
We have a few different kinds of hermit crabs in the Touch Tank.  Above was a flat-clawed hermit crab--using a moon snail shell as it's home.  Below is a different kind of hermit crab using a knobbed whelk shell as its home:
As Laurel and I waited patiently, eventually the hermit crab came out a little further...:
And finally, waaaaaay out!:
Don't worry, it won't fall out!  They hang on to the inside of the shell with their abdomen which has a slight curve to it.  By the way, hermit crabs are crustaceans and have a hard exoskeleton which they molt as they grow (except on the abdomen--which is relatively soft to help it grip the inside of the snail shell.)  If a hermit crab gets too big for its snail shell "house," it'll hunt for a larger one, and might try a few different ones on to see if they like the fit.  So what actually makes the shell?  The shells are made by marine snails like this live knobbed whelk.  Carol is showing the underside--the soft squishy part is its "stomach foot," hence its scientific name "gastropod.":
Here's another resident of our Touch Tank.  The bright orange dot is basically a "water pump" (technically a "madreporite") that helps operate its water vascular system:
This critter moves around on tiny "tube feet"--and by the way, in the center of its underside is its mouth.  It can use the hundreds of tube feet (like tiny suction cups) to pry open a clam, then will extrude its stomach outside its body into the clam shell, digest the clam, then pull its stomach back into its body:
This is a seastar, or "starfish" if you prefer.  It belongs to the group of animals known as "echinoderms" which means "spiny skin."  Its relatives include sea urchins and sand dollars.  Carly is showing you the entire seastar--this particular kind has five arms.  If an arm is bitten off by a predator, it can eventually regenerate the arm:
That's all for this edition of "Off the Beaten Path."  I'll do another feature on the Touch Tank soon and show off our horseshoe crabs--one of my all-time favorite critters!

Also, in case you're curious, a few weeks ago I purchased a Nikon D7000 D-SLR camera.  The photos above were taken with a Micro-Nikkor 40mm f/2.8G lens.  I'm still learning how to take photos with this new camera--with time hopefully I'll improve!


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