Shell Crushing Strength

Blog Post By: Lilli Stanley, Sea Turtle Intern

One of my favorite shells to collect from the beach are the beautiful whelk shells. They have a spiral pattern and often have stripes and “knobs” or spikes sticking out of them. They look similar to conchs which they are often mistaken for. However, whelks are not just a shell. They are a protective outer covering made by the whelk snail that lives inside of them. The spiral design of these shells are formed when the snail uses its mantle to produce calcium carbonate to extend their shells around a central axis, producing “whorls” or turns.

Loggerhead sea turtles love Whelks as well, but they are less interested in the shell than what is inside. Loggerheads use the strength of their massive jaws to crush the whelk shell so that they can eat the snail inside. Their strong jaws are what gives loggerheads their name. They must have a large head to be able to exert more than 500 pounds of force through their crushing jaws. Besides whelks, Loggerheads also love to eat jellyfish, mollusks, horseshoe crabs, and other species of crabs.

Since being at Edisto, I have become even more interested in whelks and got to spot a live one moving along the waters edge at Botany Bay last night. Even though the broken whelk shells may not be as pretty for collecting, I like to imagine that a Loggerhead got to it first and broke it apart for a sea turtle snack.

Live whelk shell at Botany Bay