As you may know from reading this blog, one of my favorite sea creatures is the Giant Australian Cuttlefish, Sepia apama.  These magical creatures, have a lineage that dates back to the Cretaceous period, 66 million years ago, when dinosaurs still roamed the earth.   Biologically, they are astounding, having 3 separate hearts that pump blue-green blood throughout their bodies, eight arms with suckers that are capable of taste as well as being sensitive to touch, and two separate tentacles with tiny toothlike structures for grasping prey.  I have seen them shoot these out like harpoons to snatch small fish.  They are highly intelligent and have unusual ring-shaped brains that form a circle around their esophagus with bundles of nerves extending into their arms.   Their eyes have W-Shaped pupils and they have the unique ability to see both in front of them and behind them and they have no blind spot.  Apparently, they see in black and white since they only have one color-sensitive protein in their eyes but they can perceive various colors by rapidly adjusting their eyes to capture the various light wavelengths of different colors in a process called chromatic blur.  It is believed that cuttlefish are able to see while they are still in their egg sacks since their eyes develop very early. 

Of particular importance for this specific article, the Giant Australian Cuttlefish have a wondrous ability to rapidly change the color, shape, and texture of their skin in a way that is absolutely mesmerizing.  They have three skin layers:  chromatophores that present as yellow/orange/red/brown/black, iridophores that appear iridescent or metallic, and leucophores that reflect light and may appear as bright white, red, or blue.  In normal circumstances, cuttefish use these cells to camouflage and blend in with the environment.  However, during mating, Giant Cuttlefish use these abilities to put on a shimmering, undulating display of rainbow colors to woo their mate and sometimes to intimidate competitors.  I had the amazing opportunity to witness this mating ritual yesterday and it was truly a natural wonder to behold. 

I had started off my snorkel and began tracking a single large red cuttlefish as he made his way through Cabbage Tree Bay.  Usually, they stay to themselves but, after a while, he came upon another cuttlefish and his behavior changed rapidly.  Both of the Giant Cuttlefish enlarged themselves so they appeared maybe 2 or 3 times as large as usual.   As they did this, their colors began to change and their bodies glowed and shimmered with a myriad of colors that passed across their bodies like waves of light.   It was as if they each had swallowed a rainbow and it was pulsating throughout their body radiating out through their skin.  I have never seen anything so captivating to watch.   Check out the video below!

On a more somber note, Giant Cuttlefish have brief, sharp solitary lives of only 1-2 years.  They come together once in their lives for a spectacular mating season after which they go through senescence, whereby their bodies fail and decompose within only a few months.  I imagine this looks something like when Obi-Wan Kenobi dissolved into dust leaving only his robe and light saber behind.   The female receives a sperm packet from the male and she fertilizes the eggs very shortly after mating.  She places them one by one under a rock and secures them with a sticky substance.   They are left to develop and hatch on their own which occurs 3-4 months later.  The young are very small when they hatch, only about 6mm but they grow to about 25 mm or an inch within a month or two.  Hopefully, I will be able to find some of these babies in a few months!!