Beachcombing on Tybee Island
Have you ever found something on the beach that you couldn’t identify? It appeared to be a creature of some kind, but you just weren’t sure! In the olden days, we had to go to the library or pull out the home encyclopedia to do a little research, but now we can look up things on the Internet. Please don’t kill any live creatures that you may find! You might see one of the following oddities during your beach walks on Tybee:
This is an egg casing “laid” by a whelk. Ranging from a few inches to a couple feet long, the egg casing looks like the spine of an animal, but you can tell the kids it’s more like a string of chicken eggs. If you open one of the sections, you can see numerous baby whelk shells. If this casing had not washed up on the beach, each of those tiny shelled creatures would have grown larger, just like land animals do. The soft creature inside the shell grows and its hard
shell gets bigger also, similar to the bones in human skeletons. The knobbed whelk is the official State Shell of Georgia, because it is commonly found in this area. All whelks are “univalves,” meaning “one-shelled” creatures. The whelk is related to the conch shell, which is commonly found in the waters surrounding South Florida and the Bahamas, or in Tybee Island gift shops.
Oysters, clams, coquinas, angel wings, arks, and scallops are “bivalves,” with two shells connected to cover the soft ocean animal inside. If you find both halves of a bivalve, you were lucky, since the membrane holding the two shells together deteriorates after the creature dies and the shells dry out.
Look at the small holes in these ark shells. They were actually drilled by another shelled creature, probably a moon snail or an auger! Those predatory creatures have a “tongue” like a file that enables it to puncture shells and slice up the creature inside, so it can slurp the prey right out of its shell. The resulting holes in the shells make it easy for humans (or mermaids) to string the shells to make beachy jewelry.
A beach newbie might wonder why somebody doesn’t clean up all those ugly sticks and “things” along the sandy shore. That’s called “wrack” and is merely dried marsh vegetation, seaweed, and pieces of other natural material. If you look closely, you will probably see small live animals, like crabs, nibbling on that stuff. The birds prey on the crabs, so it’s all part of the coastal food web. The word “wrack” probably comes from the word “wreck” and the wrack line shows us how high the tide came onto the beach most recently. You can often find shells and coral within and around the wrack line.
Everyone loves the sand dollar, a natural work of art! Please do not take the live ones; keep only the ones that have already died. This graphic explains the difference. To learn more about the wonderful treasures of Tybee Island, plan to visit our Marine Science Center, located near the pier and pavilion, between 15th Street and Tybrisa (16th Street). They have great educational exhibits, regularly scheduled beach programs, and a fun gift shop. www.tybeemarinescience.org
source for whelk photo…..no copyright notice stated……http://capecodartandnature.blogspot.com/2011_03_01_archive.html
source for ark shell photo…. http://fossilsandotherlivingthings.blogspot.com/2014_07_01_archive.html