A PRE-POST ON MY REEF CREATURE

Hawaiian flowers - CC

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Now, Voxters of the Sea, my next post will be about the exotic, mysterious, and beauuuutiful world of Sea Creatures! I thought I would continue my ocean theme I had going.

The problem is, my animals to be featured are cephalopods - highly strange and misunderstood creatures. All cephalopods are mollusks, also very bizarre and poorly understood creatures. Mollusks are invertebrates - also highly misunderstood and weird creatures!! Can you see why it took me four days of thinking about this?

So before my next featured creature (which you will all love), I must give some facinating background. More fun than a barrel of monkeys, I promise.

INVERTEBRATES: In the animal kingdom, there are animals with spinal columns (vertebrates) and those without (invertebrates). Now, vertebrates include fishes, amphibians, reptiles, birds and mammals. So most "animals" in the animal kingdom are vertebrates, right? No. In fact 97 PERCENT of all animals in the world are invertebrates. Only 3 percent of animals in the animal kingdom are vertebrates. Humbling, isn't it?

MOLLUSKS: When most of us think of mollusks, we think of clams, or at least slimy sea creatrues with shells. In fact, this is one defenition of a mollusk: marine creatures, most of whom have shells. But some mollusks do not have shells. The other definition of a mollusk is a creature which is kind of slimy like a clam. All mollusks have those kind of strange bodies. 

One part of the body is what you think of when you look inside a clam shell: that kind of gooey mass of nothingness, right? It's just kind of a blob. That part of the clam's body is called the Mantle, just so you know. The other part of the clam's body is the foot. It's the part that can stick to rocks and stuff. It helps mollusks like clams dig, move and swim. And of course, when we think of mollusks, we think of pretty, intricately designed shells. Types of mollusks with shells include clams, oysters, snails, mussels and conches.

Types of mollusks which don't always have shells are known as CEPHALOPODS. Cephalopods are also defined by their unique body shape. Why are cephalopods facinating to us? Well, they are considered to be the most intelligent invertebrates in existance. Read more and you'll find out how scientists have discovered that squid have their own language, and why octopuses can perform tasks that are on the same level of intellegence as a human child.

CEPHALOPODs are mollusks which are shaped a bit differently than other mollusks. Cephalopods include squid, octopuses, natiluses and cuttlefish. Ammonites have external shells. Cuttlefish and squid have a small internal skeleton which keeps them buoyant. Octopuses have no shell or internal skeleton at all.

MORE FACINATING FACTS ABOUT CEPHALOPODS:

* Cephalopod means "Head / Foot". Cephalic means "head" The head part of a cephalopod is what we were calling the mantle in the other mollusks. This refers to the large head that you can see clearly on an octopus or squid.  

Pod means "foot". * The "foot" on a cephalopod is not the large squishy thing you see on clams; rather it has been modified to be a series of long dangly arms. Octopuses have eight arms. Don't confuse arms with tentacles; tentacles are longer and thinner, and are somethimes used for grabbing things.

So scientists use the term "CEPHALOPOD" to describe the kind of mollusk that is, shall we say, "all head and foot". They're one giant head with arms and tentacles dangling ominously below its haunting stare. Now we're getting somewhere, people!!

* Cephalopods have three hearts. Two smaller ones near the gills, and one larger one below that.

* Cephalopods move through the water by jet propulsion. They take in oxygenated water into their gills and spit it out through a fold in their mantle. This is a very tiring way of moving around, and they often have to move backwards in the water.

* Cephalopods have very special skin cells that allow them to light up and change colors. These cells are called "chromatophores". Chromatophores are one of the most important elements in studying squid communication. More on this later.

* Cephalopods have some of the largest and most complex eyes in the animal world. This makes them very interesting to study, since humans also rely on eye contact to understand each other. More on this later also.

* CEPHALOPODS are the only mollusks that sleep.