#speciesoftheweek: The clam

Every once in a while a video of a "clam with enormous tongue licking salt" appears on YouTube and goes viral, collecting hundreds of thousands of views, likes and shares. A few days ago, it happend again. This video came up with a "wow" effect:

A little bit surreal, isn't it? But indeed, this is what we call a clam, a type of mollusk with the ability to open its shell if necessary and to close it again in case of danger. The video above is reason enough for us to name the clam this week's #speciesoftheweek.

More than two years ago the Daily Mail already had an article on the clam and, it seems, the very same video footage. The clam on a table with salt scattered around it pokes its tongue out of its shell, and starts to consume the salt around it. That's how it seems, but far from it! "The clam is not eating salt," the newspaper quoted an oceanographer as saying. And further: "'That appendage isn't the clam's tongue, it's the clam's foot."

So, what the clam in the video does is not eating, but probably trying to finde some place to hide, because clams usually use their feet to move and to dig into the ground where they spend some time of their lifes - buried under sand or mud.

The clams diet does not usually include salt in particular. The mollusks feed on tiny plants or animals, filtered from water and sucked in by the clam's siphons, or straw-like appendages.

However, "clam" is a very wide-ranging term, referring to those creatures of a microscopic size to the giant clam, which can weigh 200 kilograms. Some have lifecycles of only one year, while at least one has been discovered that may be over 500 years old. Also the word "clam" has different meanings.

It can either refer to all bivalve mollusks. Or, in the more limited sense, it refers to creatures living in the bottom layers of the ocean. Many of the edible clams oval in shape. Their shell consists of two parts, connected by a hinge joint and a ligament. With the help of the ligament both parts can be opened. Clams also have kidneys, a heart, a mouth, a stomach, a nervous system, and an anus.