I have to admit that I have really been impressed by the series Life on the Discovery Channel. Even though I know the show will be rerunning in 2014, by which time I'll be groaning at the very thought, right now I'm enjoying it. Those two hours last Sunday were particularly nice as a wind down after a huge midday meal (something I am not at all used to).The second show was "Creatures of the Deep" so of course your humble hostess was paying special attention (as no doubt were all sons and daughters of Poseidon). When today's special monster came on I was, quite frankly, in awe. So I thought I'd share a little naturalist info about a creature with a cute name and some unusual talents: the cuttlefish.
Cuttlefish, of the family Sepiidae, are cephalopods just like octopii and squid. Interestingly, they may be the smartest of the cephalopod family. They all have a shield shaped body with fins that extend out on either side. When the animal is swimming the fins flap like wings, making the cuttlefish look rather like a ray or skate when in motion. Rather than bones or cartilage, the body of a cuttlefish is given form by an internal shell known as a pen or gladius. You've probably seen chefs on TV remove these from squid before. Cuttlefish vary widely in size, from an inch and a half long to the giant variety that grows up to five feet in length. The animal has the ubiquitous eight legs plus two retractable tentacles for snatching up the fish and crabs these guys dine on.
It's the getting of dinner and the avoiding being a meal that makes the cuttlefish particularly fascinating, at least to me. The animals have 10 million chromatophores, or color cells, in their skin which allow them to change color at will. And it's not just a flat, single color. As the picture at the header shows these guys can imitate stripes, spots and just about anything you can imagine virtually at will. Muscles attached to the color cells move them subtly to make the colors change, as the Discovery show noted, as efficiently as a TV. How cool is that?
The cuttlefish uses this ability not only to hide from predators but to confuse and trap prey. They switch their colors quickly in kind of a rolling pattern while chasing fish, essentially hypnotizing dinner so that it's no trouble to catch. Science fiction eat your heart out.
Of course, there's always the issue of making babies and when that little segment was over the First Mate turned to me and said: "Female cuttlefish are kind of slutty." I guess it's all a matter of perspective really. The females basically lure males, get them all hot and bothered and then - if the particulars don't work out to her liking - move on to one of the other males that have been attracted to her scent and behavior. If you want to call that slutty, fine. Another way to look at it is trying to ensure that your offspring are best able to survive. It's tough out there for a cuttlefish.
But don't take my word for it. Click over to Discovery and see a cuttlefish warding off a rival (slutty the girls may be, but the boys have that aggression thing going for them) and follow a tutorial about all things cuttlefish. I'm betting you'll find it worth your while. Oh, and feel free to bring the kids. The Discovery site seems to have left out the slutty.
4 comments:
Ahoy, Pauline! What I meant by "slutty" was the fact (as shown on the show) that the female Cuttlefish will mate with multiple males (and sometimes with a second male who cleverly disguises himself as a female to fool the first male into letting him past without a fight so he can get to the first male's chosen female). Then, after she mates with the second male right under the first male's nose, she lays eggs that have been fertilized both both males. I guess you can't really blame her for wanting to have babies with the biggest and strongest as well as the guy who may not be as big and strong but is still cute and clever, but still, it just seemed a little, well, slutty... I know I'm anthropomorphizing and I'm not really trying to be judgemental. I'm just saying, Pirate Queen... ;-)
Ahoy, Timmy! Yup. She just wants the best for junior. It is like that in nature...
Oh, that's nothing unique. There is a concept in biology called 'sperm competition.' In a lot of species, the competition for reproduction doesn't end at the vagina. A female will mate with multiple males, and then the sperm of the various males compete with each other to fertilize the ova. Even among housecats, it's likely that kittens from the same litter have different fathers.
There is debate whether there are biological mechanisms for sperm competition among humans.
Dr. Tatiana's Sex Advice for All Creation covers this and a bunch of other morbidly fascinating subjects. It's written as a newspaper advice column, if bedbugs, praying mantises and splotched lizards wrote into newspapers. It's very readable and very well researched. Probably nowhere else will you find an agony aunt giving your species advice on when sexual cannibalism is a good idea. Can't recommend it enough.
Ahoy, Daggar! Great stuff in all three paragraphs, my friend. I surely do want to know when cannibalism pays, among other things.
It seems like most species are pretty good at making sure that nothing goes to waste. Humans in particular and primates in general, however... Well, that's another story.
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