Chances are you’ve seen some example of zefrank’s work if you know what the internet is, but just in case, I’ll go ahead and promote him a little more. He featured one of my favorite genera, cuttlefish, in one of his informative “True Facts” videos, and by “true” we mean more true than, “Based on a true story,” but perhaps not exactly 100% bona fide in every niggling little detail. Nevertheless, you will still learn something, even if you’re a marine biologist specializing in Sepiida, though the application of this new knowledge may have some limitations…
A few years back, The Girlfriend and I were visiting the NC Aquarium at Fort Fisher, one of three in the state, and stayed for a ridiculous amount of time at the tank housing the cuttlefish. There’s something remarkably graceful in their movements, floating in any direction without apparent effort like a helium balloon that’s lost too much pressure to rise very far anymore. But it’s their skin that deserves (and gets) all the attention. Not only are they capable of amazingly rapid and versatile color changes, for camouflage, threat displays, and mating, but they can produce bioluminescence as well, a pleasant green glow from their undersides reminiscent of those lightsticks that we enjoy playing with but can’t figure out why. I was lucky enough to capture this while we were there.
This image, or at least the background thereof, is heavily edited to remove both reflections and the rest of the aquarium showing through the back of the tank, but the cuttlefish is untouched (perhaps unretouched, whatever that means) and that green belly is indeed glowing. My understanding is that this is a mating display, the cuttlefish equivalent of an open shirt with gold chains, but likely far more effective – maybe this means guys should hang a lightstick around their neck in clubs? This might work only on the women that resemble cuttlefish, so your call on the value of that.
This one is either a European/common cuttlefish (Sepia officinalis) or a pharaoh cuttlefish (Sepia pharaonis) – the aquarium has had both and I did not confirm which one this is at the time. I was using the cheesy video function of the Canon Pro 90 IS for short clips, possibly even worse than phone video if you can imagine that, so I won’t inflict them upon you, but I still caught another aspect of behavior therein; we tend to consider their tentacles like those of the octopus, flexible and compressible but of a fixed length, so when they stretch out to twice as long as the cuttlefish’s entire body (which might even exceed the girth of their brain,) it’s a little startling. And like most aquariums and zoos, you can also capture human behavior – The Girlfriend and I still mimic the youth who approached the tank while I was filming and announced, in a broad southern accent, “That’s a squeed!”
While typing this, it occurs to me that a certain amount of how appealing cuttlefish are comes from those eyes. They’re as wide open as any fish, but the peculiar shape of the pupil gives them a mostly-closed appearance, pretty mellow and easygoing – with the intense, startled look of a round pupil, we’d very likely be interpreting the actions and intentions of these cephalopods entirely differently, since we’re a species that finds it crucial to read emotions through eyes. Give them a prominent supraorbital ridge like raptors have, glaring at everything indiscriminately, and they’ll become an apex predator and far less cute.
The coolest video about them that I’ve seen comes from Nova, their Kings of Camouflage segment, and it demonstrates just how amazing their abilities really are (this is a 53-minute, full length documentary, just so you know.) The camouflage is wonderfully effective, but it’s the dazzling hunting display that really has to be seen to be believed, and I don’t say that lightly. After this, you won’t be surprised by anything in the natural world ever again, and if it doesn’t make you at least impressed by cuttlefish, much less a fan for life, I will gladly refund your money. I’m that confident.