Hello my name is Charles Cephalopod. You may call me Charlie. I'm here to tell you about my distinguished Class of molluscs. We are the smartest, (of all the invertebrates) fastest and the most handsome (in my opinion) of all the molluscs. We are a most ancient order and are well represented in fossil records (Ammonites are our most famous ancestors). We live only marine (salt-water) environments and there are around 700 species of cephalopods living today. Some members of my Class are the octopus, squid, cuttlefish and nautilus.

Octopus

Squid

Cuttlefish

Nautilus

All my cousins and I have large heads and very complex brains. We also have two eyes and use them to see almost as you humans do (Our optical nerve is of particular interest, being amazingly large. It has been used to study how optical nerves work). We can think through fairly complex puzzles (like where you hid some food in a maze) and remember how to solve them faster the next time.

The only cephalopod with a true shell is the chambered nautilus.

The argonaut has a shellac-like structure but this not a true shell.  It is but a brood case (sort of cradle) to hold the eggs until the young hatch. This case is not attached to the animal and is held in place with one pair of her tentacles.  After the Agonauta (the argonaut genus) mother is through with this egg case, it is left to float on the ocean, and is often picked up by men, who call it a "paper nautilus".

Argonaut egg case Picture courtesy of Guido Poppe

We have cells in our skin, called chromataphores, which enable us to rapidly change our skin color and pattern whenever we want to. Example: if we get mad, we go a blotchy red color; if afraid we go a very pale almost white color. We can change our skin color and pattern to match our surroundings as well; this is called being able to camouflage ourselves.

If an enemy threatens us, we squirt out a cloud of purple-black ink, which confuses them and we jet away. This ink is also toxic or poisonous to our enemies such as sharks.

We all have arms modified with sucker discs with which we capture, hold and pull our food to our hard parrot-like-beak of a mouth. Octopus have eight of these tentacles. Squid have ten (called decapods) tentacles. The cuttlefish and nautilus have many. If we ever lose one of these tentacles in a fight or due to an injury, we just grow a new one!  The tips of these tentacles are so sensitive that we can tell the difference in size, shape and texture of objects.

I and all my cousins breath through gills, and have three hearts. We are all carnivorous predators (we catch live food) eating such things as other molluscs, fish and other marine invertebrates. We crush our food in our hard bill then rasp off bits with the radula (like a fingernail file) located in our mouths.

Most cephalopods have separate sexes and fertilization is internal. The males produce a "sperm packet" which he places inside the female s body using one of his tentacles. Sometime later, the female then lays eggs. Many cephalopods are good mothers and stay with their eggs until they hatch. They keep clean, fresh water flowing over the eggs and caress them to keep them clean of derbies. The young hatch out as perfect small copies of their parents.

(See Avril meets Charlie face to face)

Here are some interesting Cephalopod facts:

Cephalopods first appeared about 500 million years ago. Some cephalopod cans swim faster than fish. The giant squid living deep in our oceans do battle with largest whales and may eat large sharks. These giants can reach a striking 1,600 kilograms (nearly a ton!) and be 18 meters (60 feet) long - but many suspect the biggest ones haven't been found yet!!!  Sperm whales battle and eat these monsters of the deep at depths up to a km (over half a mile) below the surface - but there is evidence that sometimes the Giant Squid win the battle... Octopus can squeeze their bodies through remarkably small openings. A large octopus could easily crawl through a pop can that had been opened at both ends. The internal structure (long oval chalky "bone") of the cuttlefish is used in birdcages as a dietary supplement and for keeping their beaks in good condition.

   
For a picture of a chambered nautilus shell you can print out and colour, click HERE